First, I am not a doctor, just a mom. I’m relating my own experiences and not giving medical advice.
There was a time (in my youth, when dinosaurs ruled the earth) when doctors believed that tonsils somehow caused sore throats, since after tonsilectomies kids got fewer sore throats. Later, it was found that the rate of infections was the same in those who kept the tonsils and that the supposed cause and effect was a mirage.
From what I’ve heard, two of the valid situations when they should be removed are (1) if the tonsils themselves (not the throat or middle ear) have repeated infections, or (2) if they have become so enlarged that they impair breathing or swallowing. I have also heard of a very few cases where it was definitively determined that the tonsils were harboring a secret stash of strep germs that weren’t being killed off by antibiotics, and this was causing repeated strep throats.
Many children in the early school years get repeated sore throats and ear infections. If the throat culture shows strep, docs usually prescribe an antibiotic to prevent the strep from causing scarlet fever and/or heart valve infections. When my kids got earaches and if the doctor could see that there was an infection there, he generally prescribed antibiotics as well, since it’s kind of difficult to get a culture from behind the eardrum. Some of my co-workers now tell me that another procedure these days is inserting a tiny tube in the eardrum so that fluid drains instead of contributing to an infection.
My kids got tons of sore throats (a few of which turned out to be strep) and approximately a million ear infections. At least it seemed that way at the time. The number of both of these gradually decreased until by about 6th grade onward they rarely had any. Neither had a tonsillectomy and both are absolutely fine now. But that’s just my experience with a sample size of exactly two.
I would definitely suggest asking your doctors to explain exactly why they feel a tonsillectomy is warranted, and what they expect to happen if it isn’t done. If they can’t explain further than “it will keep her/him from getting sore throats,” I’d be suspicious. I would probably get a second opinion also before proceeding.
As far as possible problems, AFAIK complications from tonsillectomy are quite rare. I had mine out when I was a teenager, and they used a local anaesthetic since it is safer. I found the whole process horrible. The sore throat afterward is pretty nasty, too. But I didn’t have any medical complications. That’s another “ask the doctor” question, but I’d be surprised if the rate of complications wasn’t vanishingly tiny.