Laur…..all of the people you mentioned....they all KNOW about him....I will bet my fortune that they do......even his family knows...down deep---and, any details that they don't already know...they will find out pretty quick, after the split.
After I divorced my first husband...who wasn't even an alcoholic....people who knew us, later said to me..."We didn't like how he treated you"...."We weren't surprised"....
I was so shocked---I asked them..."Why didn't you say anything?!"....they all replied...."We just didn't want to interfere".....
Remember, that other people are able to be more objective than you...because you have more skin in the game....You have had a dog in the fight....lol, etc.....
His family is probably blinded by their own denial....yes, blood is usually thicker than water...but, if he lands on their doorstep...they will get a piece of him!
for you, the least interaction that you have with his family and ex wife...the better your reputation will look, down the road.....not that you should worry so much about it---but, it will just decrease another level of conflict and stress in your life.....