Before I respond, let me start by saying that I'm contributing my opinion and you may be a bit offended by it due to what you currently believe, but that I do wish the best for you and that I do not intentionally mean to offend you and I am simply contributing to you what I believe, in hopes for the best. But if you don't wish to get offended at all, do not read below the line. And this goes without saying for anyone who believes in military-service. I am simply offering this post to you as a new perspective, a new way to look at your position and circumstances, and to see a silver lining among what you see only as dreary rain clouds.
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Now let me preface this by stating this: I think military service is completely delusional and essentially just suicide.
If you read that and aren't truly disgusted by me then you might as well read the rest.
Honestly and personally, I think that not being able to join the military is the best thing that could possibly happen to you, or to anyone who desires it so much.
Coming from a 'military family' it is no wonder you've not really questioned this desire. It is an expectation, and it is honored and revered. It is essentially a dogma which the family follows. And those in these families who wish to seek and gain honor, and not to be filled with worthlessness like you have been, simply follow this to the end. And that does make a good soldier, by all means.
A good soldier is blind, devoted, absolutely faithful, and unquestioning. Those who are in power, those whom create the laws and make all decisions, would have it no other way. They require this dogmatic obedience in their soldiers just to maintain the status quo, to maintain their power. Because if you do not question their orders, then you are not able to question why you might kill innocent people for someone else's personal gains.
And that is ultimately all military service, entirely. Serving the selfish and self-righteous, in the most dogmatic way possible. To literally serve them for their benefit, but not for yours or anyone else's you know. And it's no wonder that such strong beliefs and convictions, no matter where they stem from, will feed down into families and expectations of their families.
Tyrant kings would have tyrant sons, whom would become tyrant rulers. These royal lines would only be questioned by others, whether it was their own people unable to withstand the daily torture, or the nobles whom would become power-hungry themselves and take it upon themselves to subtly stab the king in the back and take the thrones for themselves, or whether it was other Kings who were simply better managers than the tyrants, who'd have better armies or better tactics, and would simply take over.
And then such honor, such prestige, such great respect for these tyrants, these rulers, these kings would all fall down. No longer would they be honored, no longer respected. They would be disgusted by the following generations whom would find refuge under better rulers, with more distributed power.
And so we come down to modern day. Soldiers blindly following orders, delivering death into a battlefield that is foreign and unknown to them, fighting a war they don't even understand or know the motives to. Following orders of their "superior officer", to kill, to command, and to rule so that the gains of these wars may go to the winners, the rulers of a nation. Those who submit to no other authorities but themselves.
And you want to willingly participate in this? As I said, their refusal is the best thing that could happen to you. In such circumstances, both theirs and your own, if you were taken in you would have been marginalized, denigrated, or simply killed.
Personally, I find this a great opportunity. It gives you a chance at actually having a real life and being able to follow real opportunities. Ones your other family members have never had a chance to follow. You are able to question things now, see things for how they really are. You are given the opportunity to actually contribute to other people in more meaningful ways, rather than to simply serve the rich and powerful.
So many people I've known have come back from military-service significantly worse off than previously. They have things like PTSD, nightmares, life-long moral and ethical issues, or simply can't even find a regular job and find that military-service did not suit them well or prepare them for daily life 'in the real world'. They learn to shoot and kill and follow orders, and when they get back the world is 'so different' that many are unable to adapt to it properly at all.
You're being given a gift here. Something not offered a lot of people with your sort of beliefs, raised in families like your own. Something your father and grandfather likely did not have.
Tell me, of your fond memories of your father leaving for military duty, did you not cry? Did it not hurt you to see him leave for months and not even know if he was coming back?
Is that what you wish to do to your own children someday?
Why do you see this as such a failure? These expectations are nothing but your own. Your father likely sees this himself, having been there. I doubt he felt so easy leaving his family behind to go pursue mindless tasks he had no bearings for, never truly understanding his orders but simply following his convictions and his gut instincts.
I believe this feeling of failure of yours is because you are lost in other areas of your life. You're unable to find your 'place' in a world you're not fully physically attuned to, and that hurts you emotionally. That and the dogmatic veneration for military-duties as your family has been built upon.
So I offer you a few suggestions:
1. Refuse to take 'No' for an answer. Think hard about your dreams and what it is you truly want and find a way to pursue your dreams despite what anyone else says and despite your disability. Overcome this desire you have to 'fight' and for immediate action and to dive into chaos, and ask yourself what are your limits and where you might be able to push those things and where you need to factually draw the line.
2. Speak with your mother and your father about their feelings about military service. Not just the 'bright side' of respect, but the feelings of remorse and sadness watching their own fathers leave away for duty, never knowing if they will return. And face your own emotions about this side of things, and what this would mean for anyone who you cared about, your mother and your father, any siblings you may have, as well as any potential future family you may wish to have. Think hard about these things and speak openly about them. There is much you've likely been repressing and simply dealing with these repressed emotions will help you eliminate your sense of failure.
3. Finally, think hard about why you'd have wanted to go serve a government. A government whose motives are always questionable, and visibly lacking in a multitude of areas as evidence has shown time and time again. Why you'd essentially want to serve the 'modern kings' of a world in chaos, fighting wars you don't truthfully know anything about, following orders from people who are merely following orders, some of who themselves have extremely questionable morals and ethics or even entirely lacking in such.
And more importantly why you're wanting to leave everything else behind to do these things. And also, importantly, why you're wanting to serve a government that does not even want people like you or have a place for people like yourself. That may sting a bit at first, but facing our reality is the best thing we can do for ourselves if we want to legitimately accomplish something with our lives.
I think inside of you seems to be a conviction and desire to help others, from what I've picked up on reading this topic and generally knowing the type of people that I know whom you're most like. A great desire and responsibility to do something great and selfless
But truly, I hope that you question your desires and your dreams. Question your upbringing and childhood, and remember the difficulties as well as the good times. Question everything you've believed and simply just re-evaluate everything. Look at the world for what it really is and don't ask yourself how to follow your youthful dreams in some movie-like preponderance, but instead ask yourself how to follow your true beliefs in reality and in real life, against all obstacles.
I hope I didn't offend you too much. I know a lot of what I said goes against everything you grew up with and your family's beliefs, but if you've ready this far, I hope the best for you. Be careful in whatever you do. I'm just saying that sometimes these gray clouds can really be beautiful.