I remember my grandma used to host similar get-togethers party often. Middle class asia in the 90s, massive amounts of food, lots of noise and laughter, children running from one corner to other, men in their "designated" areas smoking and playing carrom board, women gossiping in the terrace and helping out in the kitchen...
yeah, it may sound sexist and outrageous in 2022, but culturally, guests are not allowed to help out the host, it's considered a sin and an insult for the host to even articulate that she needs help. My grandma always relied on me to set the table, which I did with pleasure. She was old with joint and heart issues (this was the days before modern medical solutions) and I was very aware of the fact that she won't be with us for long and it was a joy to help her out, and also a matter of pride for me that she trusted me enough with her costly china, and set the table.
Yes there was misogyny and patriarchy at the table too, also some bitter bad blood between some of the family members which created drama but none of it eclipsed the love I had for my sweet grandma who'd painstakingly make all my fav dishes during each of this party. We saw each other only a few times a year but the blood bond between us was solid because I... don't know, she told me funny stories and she smelled comfy and motherly, and she was my grandma so I just naturally loved her, I suppose.
OP, not everything is about gender/identity/value politics and whose turn it is to help out. It looks like your daughter has said no to the parties, which is good, she has set a boundary. So just say she has classes or has a job or whatever when she is missing from the next party and don't stew too much for a 85-year old woman's actions. What I'd like to know is how is the grandma normally treat your child?
Has the grandma been close to your daughter historically, does she send gifts or is very fond of her, or is she just a distant relative vibes that your kid sees thrice a year? I want to also know more about your daughter's perspective in this, why is it so awful for her to do some light chores three time a year, for her own family, especially if its cultural and if all her other cousins did the same before it was her turn? Does she not think that it would be the right thing to do for an elderly person, her own grandmother, a few times a year when said grandma spent probably hours in the kitchen preparing a delicious spread for all of them?
The world needs people with more compassion and kindness but I am sure that by itself is an outdated opinion.