Scheduling help

Hi guys — my 1 year old is on a strict schedule (I don’t want to debate this part). My grandmother is dying and she’s at home where she’ll be spending the last few months of her life. We committed as a family to see her tomorrow after my son’s nap. She lives 30 minutes from us. My son is on 1 nap a day from 12-2. He goest to bed at 8pm so this allows us a solid 4 hours to spend time with her. My husband asked me today if we can invite his whole family to our house tomorrow evening for a bbq after we see my grandma and before my son’s 8pm bedtime! This just threw a wrench in everything. I was feeling frustrated because I really wanted tomorrow to be about my grandma and we only have so much time to be with her. I don’t want to think about having to leave at a certain time or get our house ready for entertaining. Tomorrow will be very emotional for me. I can’t imagine going from seeing the person I love the most to a bbq and pretending all is ok when it’s not. I can, however, empathize with my husband. My husband’s sister in law is in town until the 5th and she hasn’t yet seen our house. He wants her to. They don’t see each other often and she’s in town for the holidays. We spent a lot of time recently with his sister outside the home. I’d love for them to come over but it’s such terrible timing although my husband said he can make it work. His plan though doesn’t allow my baby to follow his schedule and would certainly throw him off. We are trying to come with a plan to make it all work and it’s just feeling so complicated to organize seeing my grandma, my babes schedule and hosting a bbq for my husband’s family 😭! My husband isn’t happy that I’m reluctant to hosting a bbq after seeing my grandmother and doesn’t think I’m flexible enough.Maybe I need an outside perspective because I’m a little emotional. Any ideas? And my husband starts work on Monday so that wouldn’t work.