As long as he is physically able to take care of himself and can mentally make financial decisions he should be fine. it depends on the degree of hisdisability, if he needs someone to care for him and make all decisions for him on a daily bases then he will be more than likely placed in a home unless family will take him in. however if he is still capable of taking care of himself physically and mentally he will absolutely be able to stay where he is. just to be safe I would appoint someone you trust not to put him in a home as his guardian when you pass away to ensure he cannot be placed in a home.

You want to keep the government out of your son's life as much as possible.
Pleass don't access anty programs until you set up a special needs trust for the young man. I assume since he does have a traumactic brain injury, his needs are great.
With a special needs trust, all porperty , including any cash will be withiotn the trust desginated for "extras" and mean to keep him where you want him. If he becomes a state ward, the state can place him where they please.
Once he has a trust and a conservator /trustee, he maybe safe from any interference from the state. Then it will be "safe' to access special programs and entitlements.
After you have his legal status secured, another org you can check out, is volunteers of america.

You see, if any state emp[loyee, official believes he is not being cared for, they can report his "abuse" or "need" and the state will step in, and attempt to involuntarily make him a ward of the state, once that has happened, he nor anyone else, has any conmtrol over where he goes or what he does; the person loses all of the their civil rights, except what the state allows them.