I'm worried because my best friend has asthma. what can i do to help, what do you suggest?

A few things: When you are together and a third person starts to smoke, be the one who asks that person politely to stop. Before the two of you go mountain-climbing, ask nicely, "did you remember your inhaler?" the worst situation for an asthmatic is being a kid in a house full of indoor smokers. If this is the case and it's what's keeping your friend sick, write to his/her physician.

See allergist: The best way to avoid asthma attacks is to avoid the triggers which your allergist can help you pin down. The next would be a controller program of medications which keep the inflammation in the airways in check. Thus i think you can suggest to your friend to consult an allergist.