I did not say that Chrome SHOULD remain above the fray. I said it was a great option.
We are agreeing, in essence, on what boundaries are. The why's, the wherefore's, the when's, whether his W is right, wrong or indifferent... whether she is ethically, morally or socially correct in her actions, are not my concern. Those are Chrome's concerns. Do I have an opinion. Well, of course. But that is not what Chrome was asking for. He was asking about boundaries... not why or why not I think what his W and MIL are doing are right/wrong/indifferent.
Okay?
It is up to Chrome to decide what his boundaries are, when they have been violated, and some potential options he has, when they are violated. What I think he should do... is irrelevent.