2X2Many - my view is probably skewed by my up close and personal view of MLC, but, I would not bring up him ending it with OW because how will you even know if what he tells you is true? So, why bother?

You probably need to prepare for two possible options: responses for his complaints about his parents' place and for him asking outright to stay there.

Nice to hear an update and have a great 4th!

Me 41, H 47, M 15 yrs, S11, S13
BD 1: 11/4/14 we work on it; really I pretzel myself
BD 2: 3/31/15 H goes down to "dorm room"
8/15: H back to MBR
10/15: H back in dorm room
1/18: H files, now divorced