Hi K.,
My daughter had the same surgery 3 years ago and the most important thing you have to do is to make sure your son eats...
I don't want to scare you, but this a surgery that involves sedation, and it's going to be pretty rough for him after the surgery as it will be for you when coming back home. We had an amazing team of doctors and they prepared us very well before she had surgery and one of the things that they told us was to ask her to make a list about what type of foods she liked the best and have them ready for her after the surgery. "Buy her whatever she wants.... No matter if it's Junk food..." the doctors said. The pain your son will experience when swallowing after surgery, is not going to make him feel like eating and it's very, very important that he eats, the sooner he starts eating the sooner he will recover. So, like me in the past, I know you want to give him the best nutritious foods, specially after coming out from surgery, but keep in mind that what you want him to do is to start eating as soon as possible, even though if it's uncomfortable for him, and this is not the time to be picky and to be thinking about processed sugary drinks or junk foods.... The most important thing here is for him to eat....
Take him to the grocery store and ask him what would he like to eat after coming home from the hospital, let him decide.... Chances are that he will not end up eating much of what he'll pick, trust me, because as I said before... It's not going to be easy for him to eat right away at the beginning. One thing that my daughter ate was shredded ice with flavors, ice pop and ice cream. That felt always good and kept her eating...
One thing I bought was straws, they will be very helpful for your son when drinking.
You'll see him bouncing up and down in no time...... Good Luck!
Jessica