He could also look into some really really good yoga teachers.
YOGA FOR SCOLIOSIS this has a lot of questions and answers on it
He would need to find somebody probably in the iyengar tradition , which is very much into anatomical correctness and aligment of limbs, skeletal structure and such and is really quite a lot of fun too. He would need private lessons to start with anyway and as I said, only if he has a teacher who has experience with such severe scoliosis. Yoga really adresses balance and focuses on lengtening the spine and keeping joints supple through postures and breathing.
the great thing about yoga is that you get a great feel for your body and a good awareness of tension and relaxation in very specific parts of your body which is also very good for pain relief. So he'd be taught to counterbalance the disbalance so that it moves to an equilibrium. You'de hope to very gently make the curve less, so that there would be more length in his spine.
And especially seen as he's so young there is a lot of room for improvement. Your muscles , bones and joints are bound to be more flexible and you can teach muscles to become strong so as to support other structures.
One of my teachers had a hernia, quite painfull indeed and beacuse she was so aware of her body through yoga she managed to be up and going again within 2-3 months.