Ah... I'm afraid I can't take people seriously when they tell me they have Asthma and still smoke cigarettes. If he's serious about his career in aviation, he'll quit ASAP - I wouldn't be shy about mentioning that to him if I were you.
A combination of Asthma and Smoking is not very healthy, especially when you consider the operating environment at 35,000 feet.
Just my thoughts... I have no medical qualifications so maybe someone more experienced can help you more
RC