I suggest that your son starts a video type diary for the well being of his daughter and himself as well. Isnt there some sort of law there that means a spouse can 'section' a spouse for medical/mental review or go to the family doctor and say that his missus has flipped her wig or something?? There is absolutely no way your son is guilty by association at all, he obviously knows how to handle his wife. I was in an abusive relationship for 4 years and got smacked about quite badly until one day i thought, righto, enough is enough. He obviously knows that if he pushed the wrong button things could go horribly wrong and his wife could do something that would be regrettable?? I dont know, the only thing is, be there for your son and your grand daughter. Another thought, having a young baby in the house might not be a bad thing, keeps ya young and makes you smile and get that awesome warm bubbling over feeling in your heart!! All the very best of luck!!