If anyone would like an update about MIL, this us what happened:
DH spoke to her about it. Apparently, she had not considered telling someone they look gaunt is a negative thing to say but sort of accepted that it could be perceived that way. (What it is it with that family that they can never admit to having done something wrong and apologise?!)
There's a bit more to this. It always feels like MIL favours her other two grandsons over DS1 and DS2. We are always hearing how accomplished they are, and what their plans are for university etc. She never forgets their birthdays, whereas she's a bit hit and miss with my two. All four boys are about the same age. Even the gaunt thing was to do with the fact that one of them is 6ft5 and the other spends approx 4 hours a day in the gym.
So it felt like things had come to a head finally after 16 years of going unchallenged, and excuses being made for her.
DH was assuring me that if she seems unaware of our sons' good points then it's only because they / we don't tell her. So, I decided to rectify the omission because then she'll have no excuse.
A few hours after DH spoke to her about calling DS gaunt, MIL was back to boasting about her favourite DGS, who is the same age as DS1.
Over dinner, MIL tried to tell us for the second time this trip how well her other grandson did in his GCSEs last summer. I don't know what he got, apart from it was "mainly As and Bs", but I suspect DS1 did significantly better. Twice MIL told us that she'd made a special note of her other DGS's GCSE results (she has not tried to make a similar note of DS's results). So, I told her what he'd got subject by subject, and which A levels he is doing and which universities he's beginning to consider. She kept trying to butt in to stop me, indicating that she didn't like to dwell on academic successes and it's so much better when people just get on with taking and passing exams without making a fuss but I just brushed her objections aside and ploughed on.
It was really a bit of a polite stand off between us, and, amazingly I think DH was on my side!
Anyway now she knows. And next time she starts to boast about her favourite DGS again, I'll give her 5 mins and then start talking about what our two have done recently.
I know this is a derailment from year 12 talk, but parents and grandparents who make favourites and then don't even try to hide it, really appal me! So, maybe 16 years too late, but I've drawn a line in the sand for MIL over her 16 year campaign to make DS second best!