Refusing to enjoy yourself because of an arbitrary date is kind of silly. What's so special about a year? What about a month? Or 100 days? And besides, isn't it... I don't know, normal, to miss someone a little bit a lot of the time, instead of forgetting about them entirely until one day a year? I like Piratelvr1121: "something good got to come out of that awful day." Being angry at someone for not grieving the same way you do is weird (especially because said way of grieving is so strange and is probably unnatural for most people).
Back to the original story in this thread... it's possible it was made up or doctored, but I find that it could well be true also. The trouble with highly toxic people is that unless someone else has experienced something very similar, it tends to come off as unbelievable, made-up, exaggerated, or full of holes. I can't really talk to a lot of my friends about the issues I've had with my family for the same reason: they're great people (the friends, not the family), but their life experience simply won't let them take in the kinds of things that have happened. By default they'll assume things like, say, that both parties were partially right and partially wrong, and that both have exaggerated, and the best thing would be to kiss and make up. As opposed to, you know, all the recordings and concrete evidence that sadly says otherwise. It's just hard to express these things to people who haven't been as unfortunate. Nothing wrong with these people, it's just unusual for people to instantly and fully empathise with something so far outside of their personal experiences.
MIL is obviously to be avoided at all costs. Husband needs to be spoken to so that he realises that this treatment isn't acceptable and that he shouldn't sit by and do nothing while MIL refuses to let his child eat all day. Forget the MIL, she's quickly written off as evil. The husband here is potentially more damaging because he accepts this kind of thing. Work on him. Enablers are dangerous as hell, especially if you're living with one.