What do i do about my son's girl friend?

any way my son have a tramp,slut,*****, of a girl friend. evey time he bring her to my house she always has to smoke in the house,and she knows my wife is ill. she treats my son like **** and she hits my dog all the time. there was one time where she through my dog in the pool and it was cold as hell. then when the dog wanted in she locked the door. and now she can't wait to send my wife and i to a nursing home so she could have the house, and get ride of my son and my grandkids.