Wow! I'd have been hard pressed to let anyone treat my parents like that - I would have suggested to my ILs that we ALL go out for dinner, and that my husband and I would be happy to pick up the tab.
I agree, apparently her daughter did as well,note the word "former" in front of the son in law.
The above was me---and he is, and DD and her new family are marvelous, thanks. We were just both so startled, I think, standing there with the champagne glasses, especially after they came so early---DD had thought they were going to look at cars, then they came to our house BEFORE dinner.
She knew we'd been slighted, since we ALWAYS had them over a time or two, and they had NEVER once invited us out, EVER. She'd been so embarrassed that we weren't invited to dinner with them, but other than inviting us herself, there wasn't much other option. I just laughed, cut cake, and let it slide, for her sake.
We all got along ok for the next few years---not great, but with limited exposure.
There's another little scenario somewhere in EHell with above former SIL, sans his parents, involving cleaning his plate of cocktail sauce with my best Battenburg napkins, a gift from my late Mother. That family was class all the way.