He won't seek help because he's not reached his rock bottom yet
And sadly your mother has not reached hers yet either.
Is there al-anon in your area? If so you might want to go check out some meetings. Al-anon is for the family and friends of alcoholics, a face to face support group with others going through the family dysfunction of alcoholism.
Enablers can become just as toxic as the alcoholic, maybe you might want to think about setting some boundaries with your mother regarding her sharing about the chaos and dysfunction-taking place in her home, which is affecting you as well.