I too am heartbroken hearing about your son. May God bless him and your family in the coming years.
I know very little about CF, but agree that a coach should be informed about his condition, and what type of impact it might have on his ability to compete. On the positive side, I would think that having player who has a disease like CF, and wants to compete and participate at the college level would bring a high degree of motivation and bonding to others in a program. That said, there are so many variables here, such as how impacted will his performance be, will he even want it known that he has CF, to offer much meaningful advice. Many here have lots of experience on baseball related things, but few, if any, have much experience with what you and your son are facing. So I would think that you should be prepared to discuss, in detail, with a potential coach all of these issues up front as this will make it much easier for your boy should he be accepted into a program. Best of luck to you and your son.