Hmmmm... can't really help you with a MIL move interpretation. I have the MIL from h@ll, so I'm a bit overreactive on the topic.
Sounds like you handled it beautifully, pointing out the potential benefits to MIL and D3.
In terms of Ws pulling back to the 'me' focus, I'd imagine that there'd be a little threat in one's mother moving near after being away, no matter how many positives there are as well. I also guess that it makes the sitch a bit more complex, but perhaps a bit more stable, too?
Hang in there, UD. Going for a monster workout myself to give myself a boost.