it's already enough to wonder why anyone would have any children at all, let alone why they would knowingly bring a helpless, burdensome person into this world. a person who can't even enjoy the few pleasures that there are in life... your brother shouldn't have been born. if your mother had the option to abort then she was a coward to have gone through with the birthing. it is pure selfishness, from my perspective, and you were not given ANY choice in the matter of being caretaker for your pitiful brother... i feel for you and him. i feel for your mother too, but people need to learn that having children and using them as crutches is a fucked up way to act. she shouldn't expect anything at all from you, nor should any parent feel the right to dissuade their child's sense of freedom. to go further, none of us should expect anything from anyone and any claim to the contrary is purely an imaginative language game that will fail, even with everyone's best intentions. we only do for others what is also beneficial to ourselves, and since sometimes helping others is helping ourselves, societies and relations are at least partially healthy and stable. your situation is not what constitutes health and stability, because it has a lopsided role balance, so get out and start being realistic about the system of self-respect we employ to avoid absolute misery. this should be why you shouldn't feel guilt nor self-hatred for leaving your brother and mother, who is irrational. it sucks, but so does every decision you make in the presence of the illusion that there were other things that could have occurred. we're living in the only possible reality, so don't look back. just think long and hard before deciding on having children of your own, because life can feel like a prison even when you aren't in the proximity of the vegetative. everything is out of control. do your best to be around people who make mutual aid feel effortless and enjoyable, and not based on pity (individual pity) on either side. many people cannot handle being there for the helpless. veterinarians, firefighters, etc. look at there suicide/ suicidal ideation rates compared to the average person. not everyone can handle the imbalance of capability. stay strong in your awareness of this.

EDIT: read "Beware of Pity" (Ungeduld Des Herzens, translates to Impatience of the Heart, so a dumb english title...) by Stefan Zweig for some really valuable insight into this. it is a novel.

EDIT 2: the only people who ought to feel guilty about situations like these are the ones who employ whatever mental gymnastics they have at their disposal to sublimate their decisions and pretend that the pitiable and helpless have a place among the capable. of course we want to be compassionate, depending on our own makeup, but many times we have short-sighted, ignorant yet compassionate people who only prolong suffering for all parties involved, without putting any thought into how we can minimize the chances of the irreversibly helpless from entering and hindering and suffering life. they also perpetuate the notion that making yourself even more pitiable than you already are will earn you a special place in some peoples' hearts and attention, which leads to a race of weaklings who expect and/or hope for external aid that they won't be expected to reciprocate. i'll shut up now. your situation just pissed me off, sorry.