Dog advice!!

Please no judgements. My dog is sick with a prostate issue at only 2 years old. He’s refusing to eat. The vet said he needs to be neutered (this Thursday) but he hasn’t eaten in days... I’ve been force feeding him water and pedialyte

I need some help on how to get him to eat???

He’s on an antibiotic right now, can I still give pedialyte?? I tried to call vet but they said they can’t tell me until one of the doctors come in tomorrow. I’m so lost and I feel so helpless.

I tried white rice and chicken and he still won’t eat.