This is so sad, she should leave him while the little one is still small. Its much harder when children are older. He will not change he will get worse over time. Your daughter needs to make sure in her own mind that she has to leave, otherwise when the sob stories start as they will from him, things like "I will change, I cant live without you etc." she will go back to him, ideally she HAS to stop loving him to be strong enough to leave. She should not let him have a clue she will leave otherwise he will get very angry. Womans Aid is worth looking into. She is very fortunate to have such loving and helpful parents, best wishes to all of you