What are the things to be taken care before and after the surgery?

Hey Everyone! My dad has TMJ disorders for the past few years. He has to take medicines regularly. He is supposed to eat soft foods only. Every day he has to apply cold packs on side of his face. But for god’s sake, he never does these things. Eat whatever he likes, don’t take medicines regularly and don’t follow anything meant for him. Last day, when he was having an apple, he got a sudden pain in his jaws. Immediately, we took him to the clinic. The oral surgery specialists in Lexington told us that this can be recovered only by a oral surgery. I don’t know much about oral surgeries. What are the things to be taken care before and after the surgery?