He has taken 2 or 3 months off lifting and it still hurts him.. What stretches? I think it could be bad posture he sits like oldman sometimes
there are a lot of things you need to do for long term health with weightlifting. the problem with lifting is we don't get hit with injuries that are direct.. a lot of times they are nagging type injuries that we get over time and they never get a chance to heal because we keep pounding away.
a quality mattress, pillow is important.. stretching everyday and especially warming up before and stretching after workouts. yoga.. an occasional visit to the acupuncturist/massage therapist/chiropractor.. learning to sleep on the back and not the side or stomach..
if he juices he needs to be careful not to over do things as well. you are right that taking 2 or 3 months off from lifting sometimes doesn't help the situation. when i had shin splints from running i took 6 months straight off running which sucked and my shins still hurt.