First, you need to know, you did NOTHING wrong. Your family is the problem, NOT YOU.
Second, when you say you are “financially-dependent on my mother at the moment.” it’s quite likely the other way around. If you’re as disabled as you say, you should be getting disability benefits, paid to YOU, not them. Likely they were collecting before you turned 18, but at 21 those benefits are YOURS, not theirs.
Third, don’t sweat the birth certificate or SSN. Those are just paper and there’s a process to replace them, a process you can’t start if they harm you.
GTFO. Now. While you can. Take your benefits with you, cut them off and let them hang.
Mot wrong, but video links are not allowed.