S.!.
Each child is different. My son has his out at 2 yrs of age and he was a total bear. He cried and cried and cried. He wouldn't take his pain medicine b/c his throat hurt so bad and if we did get it down he would make himself puke it back up. On the other hand, my daughter had hers removed at 3 and she was eating cheez its 10 mins after she woke up. She came home took a nap and was back to playing as usual and the surgery didn't even phase her.
I would take your son shopping before hand and let him pick out a few easy foods to eat. I like to use the Liptons double noodle soup when we had sore throats or other mouth/throat issues going on in our home. Anyways, but to taking him shopping tho - my son thought it was great to pick out his own jello and posicles and yogurt and stufff. Maybe take him tot he movie store too and let him pick out a few movies to watch also.
Good luck!