How can my boyfriend's family escape an abusive mother?

My boyfriend’s family is a shambles. In the centre of it all, the mother has recently (about 4 months ago) discovered online dating and it makes her feel good when she receives good feedback. Now she has found a man she speaks with all day and everyday. She has a family business but she isn’t paying it enough attention and the house is badly in need of money with this winter where they went for a stretch where they just couldnt afford food. The youngest is 13 and she verbally abuses him whenever she feels she cant get him to do as she wants with bully-like name calling and an example today she accused him of doing something that stopped her being able to talk to her online boyfriend and she flipped out and punched him in the arm and also shouting at him. All of this when he didnt do a thing.

She’s almost like a child who cannot control herself and no one can control her as after all she is the mother and the children (though my boyfriend is 26) cannot really tell her what to do. She is often short tempered with everyone and my boyfriend can’t stand it much longer. He has to look after the house basically making sure things are ok and esp has to protect the youngest. What can he do to help the situation? To make her take responsibility? What can anyone do to make it better? I’m afraid that the answer might be that they just have to ride it out until the youngest can move out and fend for himself… but this wont be for several years yet…