Friend being financially abused by mother.

Location: Missouri

Affected parties age: 20m

I(19f) have a friend who lives with their mother in a difficult situation. He works everyday and are given no access to his savings(6k). He has to beg for money from their mom for any amount of money, even gas, will constantly screams at him for every dollar spent, and has consistently had his door taking from him by his step-father. I'm worried for him, especially since he have tried to get out of his situation, but his family bilitles him when he tries. I don't think he could stay with me, since we already have 6 people and 6 animals(two of them are my sisters). What can we do? He's an adult, he has the means to move to cheap housing if he could just have access to his money, but his mom won't let him.