To deal with or avoid...

So lately I have been faced with the dilemma of whether or not to allow my mother in law to see my son. While my son and I were away visiting my parents, hubby decided to to spend the night at his mothers and play video games with his youngest brother. His mother, being already inebriated decided to take him to the bar with her where they both consumed way too much alcohol. It got to the point where he was dumping drinks on the floor when she wasn't looking because she didn't want to stop drinking. Hubby trying to be a responsible person and also trying to protect his mother tried to get her to go home to her own bed, rather than with some random stranger, which she proceeded to get angry and tried to run out onto the highway. He tried to get her to listen and she hit him so he called the cops and she was put in the DT overnight. She is now going around trying to tell everyone that he was hitting her, and yes her arms are bruised from him grabbing her arms to keep her off the road, but hubby is not a violent person and would never hit a women no matter the reason. This closely resembles the last time she got wasted and freaked out and blamed it on hubby and hubby's brother for her own flaws, which was a month before my son was born. It seems to be a recurring problem for her to get drunk and spaz out and blame it on her children. I know she has never drank around my son, but if she can't take responsibility for her actions and blames everything on her own son I don't think I want her around my son all that much because I don't want him learning that attitude. Does anyone have any insight as to what I could do? My son loves her so much but I don't want him to be like that when he is older.