Welcome fantasyx
Although you may be able to arrange treatment for a family member, I believe he must sign himself in. He needs to make the choice. Even if its due to court order or intervention, without wanting sobriety and making the choice to live sober it may be useless.
BUT
A homeowner has legal rights as far as who may reside in and on their premises, and what conduct is allowed.
Your mother may do well to learn how to set boundaries and limits to what is acceptable behaviour on her premises.
The boundaries might include no alcohol, and they may include no screaming...
I agree that she needs to seek help and support for herself and that way your brother may eventually deal with his problem when he is motivated (the possibility of becoming homeless may encourage an honest self-appraisal)
I wish your family the best..