Friend w/ knee troubles

I have a buddy that is hopping around favoring 1 leg and was wondering if anyone had any advice at all for workouts to help strengthen his knee in hopes to alleviate his pain. He has torn the knee before when he was younger and feels the pain on the inside of the knee. When doing a squat he only gets pain when his knees go inward. When he keeps them tracking over his feet like he should he feels no pain. Also feels pain during compression on landing from a box jump. Any ideas? Thanks guys!

I will try to help you find something if I can. Perhaps eliminating that inward squat would help? If he were to do a squat, would he naturally rotate his knees inward? If so, that would be a problem to fix. How has he kept up on knee prehab as well?

Not much to go on, but I've heard that the book, "Pain Free" by Pete Egoscue is a great book about taking care of these kinds of things. Your local library may have it, but it depends on where you live.

Pressure on the inner knee?

Take away the hard landing stuff for now.

Start working single leg squatting perhaps with basic lunges, bulgarian split squat to SLS/pistol.

Does he have a valgus alignment issue as well?

Thanks for the help guys! Anything will be appreciated it. I will definitely make sure he avoids weighted squatting that could cause the knees to drift inward. I have also told him to stop doing compression moves like box jumps. I like the idea of very strict form one legged squats. Blairbob, I am not sure what the valgus alignment is but I will get some more information and get back with you. Thanks again!