I think drug use is the biggest problem here. Regardless of neuro-type people who smoke dope frequently end up doing nothing useful with their lives. Someone suggested involving the legal system, in some countries that might work but in more repressive countries like the US that would be a really bad idea, maybe even a death sentence (Aspies would tend to do badly in prison).
The option of allowing him to move in with an automated payment for food and board is a good idea. I suggest making the payment $250 per week (slightly less than the rent he was supposed to be paying) which doesn't leave much money for drugs. Have a strict policy of no drugs in your house.
Finally you have to make it a priority to care for the other kids. They don't deserve to suffer because their brother is an addict. If you live in the US it might be best to just cut him off for the sake of the other kids.
The option of allowing him to move in with an automated payment for food and board is a good idea. I suggest making the payment $250 per week (slightly less than the rent he was supposed to be paying) which doesn't leave much money for drugs. Have a strict policy of no drugs in your house.
Finally you have to make it a priority to care for the other kids. They don't deserve to suffer because their brother is an addict. If you live in the US it might be best to just cut him off for the sake of the other kids.