I understood the other day, when I bumped into his friend and colleague, that I can have a conversation and not ask about H. Doing that also helped me feel a little more dignified in this whole situation.
If MIL brings him up when she is round this afternoon, then I'll just nod and say something neutral, maybe even compassionate if I an manage it, but not ask any questions.
I feel sorry for her, tbh. It must be difficult for them as well. They were really fond of me and they saw very clearly how much I loved their son over the course of those 18 years we were together.