If his height is a disadvantage in any way I would be amazed. I am 6'4" and fly a passenger jet, and know plenty of guys my height flying for various carriers all over the world, including Virgin Atlantic, Air New Zealand, Cathay Pacific; the list goes on.
If anything it's a good thing... It means he won't have to stretch to hit the call button when he needs a new cup of tea!!!
All the best,