Wisdom Teeth Removal After Braces?

Hello, My son is 16 and he just had his braces removed. His orthodontist thinks that all 4 wisdom teeth have to be taken out. Only one tooth is barely out and the rest is not out yet. I don’t want to put my son through the surgery if it’s not necessary. Is it common to remove 4 wisdom teeth after the braces were taken out? What is the downside in removing wisdom teeth and what are the side effects? What questions should I ask the surgeon? I appreciate your advice!