AITA for refusing to make my demented mother a hot fudge sundae at 1:30 AM when she asked for it and woke me up?

I (67F) am my mother’s caregiver (94 yrs old). She gets up at night to use the bathroom many times and I never get any sleep. Taking care of her is a full time job and everyone assumes it is easy. I take her to every appointment, to the bathroom, lift her everywhere. It is a lot.

Last night at 1:30 in the morning she randomly woke me up asking me to make her a hot fudge sundae. I yelled back that it was 1:30 and to go to bed. She asked me again and I yelled at her, probably rudely and told her to go to bed and that her request was ridiculous given the time of the day. She persisted.

My nephew in the other room woke up, made her the sundae which she said she loved, thanked him, and said she does not think she will get to have many of them in her life given her age and health.

My nephews, my sister, my brother-in-law, and my niece-in-law all admonished me for not making her the sundae and said I was cruel and mean. In my mind, it was an insane request and now she is going to ask for it every night. She has no concept of time of day and I am her sole caregiver.

AITA?