I thought the whole reason Chantal's family "cancelled" Thanksgiving was because it wasn't safe for groups outside of the immediate family to gather. Yet Peetz and Chantal joined his mom along with a family friend and who knows else. Maybe there is credence to her family just not wanting her over this year? Or Peetz and his family don't care about the potential spread.
I think it's both, but mostly the first one. IIRC they were always planning to have two Thanksgivings on consecutive days, which isn't that unusual for couples or cohabiting best friends who basically function like couples, and it was only Mama Saurault who cancelled.
If we were talking about rational, responsible people, the situation we have here is two overlapping bubbles- Chantal's family and Peetz family, that overlap via our gluttonous gourmet. By just doing Thanksgiving with one mom instead of two consecutive dinners, you separate the bubbles. This seems like the easiest way to reduce risk and still have the holiday. I can't speculate as to how rational and responsible their families are. Peetz's family seems to not care, given this "family friend," but Chantal's mom could have a different perception of risk.
However, given what we've seen, and how Chantal has behaved at family gatherings, I would 100% buy that Mama Saurault grabbed at that government recommendation like a drowning man. I would not be shocked at all if the sister and her boyfriend were still welcome for dinner, and saying "We're trying to overlap as few bubbles as possible" was the handy excuse.
Without a pandemic, it's pretty hard to un-invite your 36-year-old daughter who doesn't have her own family. This was a godsend. And the fact that her mother hasn't used the pandemic as an excuse to stay away from Chantal before doesn't undercut that, I think. Mama might know she can only play this card once or twice, or she might be one of those people who didn't take the pandemic seriously until it started affecting people she knew, etc.
Either way, good for her.