Smoking of any kind is the worst possible thing anyone with cystic fibrosis can do. The smoke's not just irritating and dangerous, it also reduces their already limited pulmonary capacity.

I found this British article from 2001 on smoking and CF, which includes a mention of marijuana, which I'm sure they included because CF is a disease affecting the young. It said there've been no long-term studies on cannabis smoking and CF, but it gives plenty of persuasive reasons why a CF patient shouldn't risk it.
http://www.pubmedcentral.nih.gov/pic...4&blobtype=pdf

If I find anything else, I'll let you know, and Granny Storm Crow will likely do the same. The bottom line, I'm afraid, is that your friend needs to eat her cannabis if she wants to use it. CF patients have enough to worry about without irritating their lungs unnecessarily. There's apparently evidence that cannabinoids themselves (the active ingredient in cannabis but isolated and taken in another way than by smoking) are very beneficial for CF patients in easing broncho-constriction and stimulating appetite, but definitely not smoked cannabinoids. I found several mentions of the benefits of cannabinoids themselves. That may be why she has a prescription for Marinol.

Real sorry to hear about your friend, Loki. That's not a good disease to inherit. I had a childhood friend who had CF. My heart goes out to her and her family and friends.