He's not attending the engagement party. His family and future exDIL are losing their minds. He's turned off his phone and refusing to engage with any of them.

Today I texted SS30 and let him know how sad we (my kids and I) are about missing his engagement party. And then I sat on pins and needles, waiting for his reply. And he shocked me. He said that he was sad that we weren't coming but that he "gets it". He said hd knows that the rift in the family is getting worse, rather than better, and that it's very upsetting. (With no hint of blame tossed in my direction!). He said that "for the record" he wants me and my kids to be a part of important events in his life but that I should do what's best for me and my kids. 

My SS and his SO are having an engagement party in a couple of weeks. DH and I haven't attended any of his family functions over the past year. SS's SO called DH and asked if we were available on a particular date, without saying why. He said "yes" and now we have no good excuse to not go. And of course DH wants to go. It's his son. We already missed SS's housewarming gathering because we were conveniently out of town, and it was very painful for DH to see pictures all over fb of his disappointing family members gathered at SS's house and not him.

So, after our guests left our (2022) Easter brunch, I texted my SD and SIL to acknowlege and apologize for my mother's offensive comments. My SD responded immediately. She thanked me and said that the situation might require some further discussion, to which I responded "absolutely". SIL didn't respond at all. Which was unlike him, but I assumed he needed time to process. The next morning (Monday), I texted him again and apologized again. I also told him that I had spoken to my mother and told her that her comments were offensive.