My disabled 13 years old son was diagnosed with thoracolumbar scoliosis to the left. it measures about 16,5 degrees. and there is elevated position of the right iliac crest. does he need to wear some brace or it would be enough to do some exercises ?

Close observation: Usually intervention is post poned for scoliosus under 20-25 degrees. At age 13, however, he should anticipate more growth, and scoliosis may increase, so monitoring every 3-6 months is important. There is some controversy as to whether full time bracing is helpful, as muscles become weak with disuse. A combination of night bracing and muscle stimulation may be best.

Depends: On full examination and his ability to tolerate a rigid brace if indicated. A flexible brace will not be effective

No: No, braces are not usually used unless curve reaches 25-30 degree range. So a make that is 13 and has a 16.5 degree curve would typically be simply xrayd every 6 months for signs of further progression until skeletal maturity; which can be determined when the growth plates of the pelvis close. Again, if he got over 25-30 degrees, a brace would then be recommended.