M.S.
My boy had his adnoids and tonsils out at 3.5 years. He had hearing problems and then ENT discovered he had "XL" adnoids and tonsils. We were able to sit with him as he met the nurses and anesthesiologist. They were fabulous! They were so fun, and signing that he forgot what he was there for (they called his hosp. bed a race car and raced him back!!). They gave him some mild sedative and wheeled him back. I don't even think he knew we were gone b/c they had him so curious and in a good mood. I know he would've picked up on our anxiety so I was glad we didn't but I was glad we got to meet the staff.
It did help with breathing (prior we had to clean his nose every day). We never noticed any problems sleeping. His voice did get and has stayed at a higher pitch the before surgery.
I am pretty anal so when they said see you in 20m I actually set the timer on my watch WAITING to run to my baby. Well they were wrong... it was 15m!!! He did wake up scared and refused the popsicles. The take home meds kept him out for the day. I was warned that dehydration was the biggest complication and my son did get VERY stubborn about drinking. His recovery was about 2 weeks (b/c of removing both) and that is how long it took him to be himself. He did good sitting outside, watching movies, coloring, etc. Hopefully yours will have a faster recovery.