I have heard the driving thing is bad for a lot of them. H had even told me that right when he got back and they had mentioned it in one of the readjustment meetings. Triggers some memories for them.
When is his evaluation? We are in a better position than most because we can go through their commanders for things like that. I wouldn't think they would let him recommit to any time until they are sure he has worked through issues. I guess every commander and branch is different though. If they evaluate him though they may require ADs and counseling. Sounds like he is very defensive so probably best for you and his family to leave that alone.
His sister was put in a bad situation. I am not sure what I would do myself. One thing I can tell you from my experience is don't bad mouth him to much to your friends. Vent here and to maybe one or two close friends. The problem is that if he decides to reconcile...it is hard for them to forgive. You love him and you would want to work things out. All they see is the hurt that he put you through and don't want you to go through that again. No one understands until they have been through it...nor do they know what they would do in your situation.
I think everything will blow up with OW pretty quick. I also predict her "cheating" (its hard to call it that!) on him. You really do sound like you are doing great, and you should be proud of yourself.
