So here's an update on the situation

My father in law has finally had enough. he laid down the law with my mother in law and ordered Don out of the house. He said that he was never to come in the house again or be around his children or his grandson ( my son) and if don ever showed up again, he would kill him - which may be a little extreame, but that was probably the Jack-N-Coke talking. Anyway, it's been a bit of a falling out between them. Don has not been at the house recently, but they do work together and they do go out after work sometimes. This of course, irritates my father in law to no end. He is considering divorce, but our state is a community property state. For the non-initiated, that means he gives up a claim to half of everything, 401k, equity in the house, stocks, bonds, savings, everything but debt, of which he will be stuck completly with becuase it's all in his name. They ARE in counseling, but that is at a stalemate and will not move any further until according tothe therapist "they have a two person and not three person relationship."

My husband was in on leave for the last two weeks, and we clued him in on what happened. he has talked to his mom and dad about it and has made it clear that we don't want Turner (our son) around Don. His mom was a little offended, but i guess that her problem. I am very comforted by the fact that every family friend I have discussed this with agrees with me about my perception of him.

So for the Cliff's notes: don is a douchebag, everyone knows it but MIL and Mr. LAW has laid down the law with the family. the end.