Welcome to the forum and I’m sorry to hear of your injury.
If he really isn’t eating and his hay intake has dropped, then you will see a drop in his weight.
At this point you need to switch from the normal weekly weight checks and instead weigh him daily so you can more closely monitor his food intake. You must step in and syringe feed him and see a vet if he isn’t eating. A piggy who isn’t eating is a poorly piggy - it may be because has isn’t having interaction that he seems to be like this but they need the fibre constantly going through their guts and lack of interest in food and subsequent drop in weight require you to step in with support and vet treatment.
Does he live alone? If so, then he may be lonely. Piggies need to be kept in pairs as they requirement companionship of their own kind. While human interaction isn’t enough for them, if you have not been able to spend time with him and he doesn’t have a piggy companion, then he will notice that.
Is there somebody who can help you weigh him, syringe feed and see a vet?
Not Eating, Weight Loss And The Importance Of Syringe Feeding Fibre