When you have S5 just do whatever it is that YOU think is best for him at that time. W thinks that she is doing the same when he is with her and it is not going to help if you argue with her on this. It will just stress the 3 of you out.
H tends to try (I know he means well) to tell me things sometimes that he thinks D4 should or should not do and I just listen. I don't always agree but I do listen. Of course in my mind I am thinking "who are you to tell me...blah blah blah when you don't even live here." But I don't go there
Again, W is going to try anytime she can to push your buttons. It then gives her the feeling that what she is doing to the family is right when it gets you all fired up. Don't give her that.
I am beginning to ramble so I am off to bed. Hang in there Gabriel