Easter Lunch

There's Easter lunch at my in-laws tomorrow, my husband isn't interested in going. He told me he wasn't even asked but rather my MIL demanded that all her 3 kids with partners should be there. But also a big reason for his disinterest is since his falling out with his sister, it's awkward. On Xmas he tried to make small talk and she flat out would ignore him. Even though he has no fault in the matter he still tried to be the bigger person. My MIL saw he wasn't happy about it and made an alternative to come for Easter Sunday lunch, to which he said he needs to take care of paper work and that was the truth. At first I was trying to convince him to go after all, they had bought everything to cook. But then I thought about it and I don't think it's fair to force him to be in an uncomfortable situation just to please some people. Or we could go much later in the day. He said he needs to sleep on it and see tomorrow morning. But he feels bad that my in-laws have already prepared everything.

Do you think it would be rude to call first thing in the morning and say we aren't coming or go anyway? I wouldn't mind going during dinner to make up for the lunch , is this a good solution?