Hi my friend is 6'2'' and 215 lb, what size of shirt should I get for him, XL (72''), XXL (74'') or XXXL(76'')?

Probably a XL or a XXL.

The worry will be the length of the shirt, since he is tall, if you are buying better mens clothing, buy them in long

The XXXL will most likely be too big in the shoulders

The XL should fit if it is from a good manufactor and is long enough, but you may have to go to the XXL to get the length you need.

Also remember not all shirts are the same, I have some brands I can weare the XXL fine, in others I have to have the XXXL.

Maybe try a Big&Tall store.