Okay, so I have a friend who has mild scoliosis and he's training with me for the time being to learn the ropes and get started properly. He's 20 years old and this is pretty much the first time he's ever seriously lifted weights.
Most exercises he's doing fine on, and I expect his technique will only get better in time, but there are a few exercises that he had trouble with, namely squats and deadlifts, so I had him stop doing those until I could find out more about his back problem and lifting.
For squats, I had him switch to a smith machine because he found it easier. On regular barbell squats, his main problem was that when he went down, he wanted to raise up with his heels, and he couldn't go all the way parallel. I told him he could try to work on squatting to parallel at home by practicing unweighted squats. Deadlifts we didn't even really try.
So, if anyone has any advice or personal experiences with this type of situation, it would be greatly appreciated. Thanks!