"Should my son give up on teaching before he begins?"

Depends. If he really wants to teach, then he should give it a shot, and see how it goes. Some people, because of their brains and personalities, don't get terribly dragged down by all the stress, pressures, and general BS. Many young people, though, find themselves carrying on through a grim determination - they're going to make it to the end of the year no matter what, just the way their grandfather fought to the top of that hill and liberated Europe. Contrary to conventional wisdom, I'm not sure that that's the best attitude. Sometimes I think it would be better for a beginning teacher who's having a miserable time to just take a look at themselves, take a look at the situation, and say, This isn't a match - I'm outta here. And go work at McDonald's, if need be, till they work out something better.

One of my sons has considered going into teaching. I've neither encouraged nor discouraged him. My advice was that if he honestly thought he would like teaching, to go ahead, but if he was just thinking of it as something he "could do" with a History degree, then I wouldn't particularly recommend it.