Sport Coat for tall, THIN teen

[toby]

DS just found out he needs a sport coat for a competition next week. It is very hard to find him clothes since he is almost 5'8" and I don't think he even weighs 100 lbs. He has grown out of boys' clothes, but men's are big on him. His chest size is around 30" and arm length is 31." He has a dress shirt that is a men's small, but that looks big on him. I don't even know where to start with the jacket!

Any suggestions would be great...

[JBaxter]

Take him to some place like Jos A Banks, Mens Warehouse or a similar store and have them measure him. Kohls might be OK if you have him stand and try on jackets.