About $12-14,000 per year.
The anti-TNF drugs Enbrel and Remicade have been approved for the treatment of AS. They have been very effective. Ask your doctor.
Hyalgan is approved only for osteoarthritis of the knee in the U.S.. I have seen studies showing its usefulness in inflammatory arthritis but I do not have any direct experience with use of Hyalgan in those types of arthritis. You need to discuss your observations with your doctor to decide if they are worth it.
Unfortunately, I can’t diagnose him over the internet, but his symptoms might be related to ankylosing spondylitis or juvenil rheumatoid arthritis. He definitely needs to be seen by a rheumatologist, preferably a pediatric rheumatologist.
The departments at the Hospital for Special Surgery (Cornell) and the Hospital for Joint Diseases (NYU) are excellent.