My sister is going to Changchun for surgery because of congenital heart disease. I don't know how to manage surgeons and nurses. How much should I give you as a red envelope? Do you want to invite me

My sister is going to Changchun for surgery because of congenital heart disease. I don't know how to manage surgeons and nurses. How much should I give you as a red envelope? Do you want to invite me to dinner? My friend used to be a doctor, saying that ordinary doctors would do well without charge, but when my mother had stomach surgery, we also gave money. We give the surgeon 2000 and the anesthesiologist 500. Now we want to give more money to the surgeon. At that time, money, like paper flowers, generally didn't go out to eat together. If they can't finish the operation in the morning or afternoon, you can ask them if they need to prepare a box lunch or a fast food. I think we are overpaying, so you can give less. I'm a little uneasy if I don't give it. It depends on them.