Hi there, I've been on various doses of ibuprofen during my cf excerbations. Like you said, it's used to control inflammation. As far as the risks to liver are concerned, they must be weighed against the benefit of using this to help the lungs. I've never been on ibuprofen long term (more than a few weeks at a time) and don't know anybody who has... This really sounds like something you need to ask your son's doctor about. What I do know is that you're supposed to take it with food, never on an empty stomach because that can cause stomach bleeding. Good luck and take care.-Wes