I have a son who will be 1 in a couple of weeks. PIL were seeing him once a week, and we'd asked them to look after him overnight for 1 night a couple of months ago, as DH and I were planning to go somewhere. They were thrilled with the idea and really wanted to look after him, which we thought was natural, them being his grandparents and everything... However, a week or two beforehand PIL were looking after SIL's kids and MIL rang me on a day she knew I wasn't at home to demand that she brought the other kids round to see their cousin that afternoon. I wasn't in so I didn't respond to the call and as a result MIL sent DH an email saying they could no longer look after DS when we were away. She is a very stroppy woman and likes to get her own way. We had plenty of other people happy to babysit DS so we just said 'ok, fine, thanks for letting us know' and organised alternative arrangements.
MIL clearly expected us to ring her, apologise for not rearranging our schedule around her with no notice and beg her to look after our child as we couldn't cope without her. Which clearly we didn't do, because we thought she was being childish and petty. Since then MIL has sulked, has not contacted us in any way and has not shown any interest in our DS. It's DS's birthday the week after next and I suspect the PIL are going to ignore it because MIL's sulk is more important than their grandson's first birthday.
AIBU to be furious, and rather disgusted, that a grown woman is behaving so childishly that she will prioritise a sulk over her grandchild?