Asking for suggestions/advice

My dad is 78 years old and is currently going through chemotherapy for bladder cancer that has affected the muscle of the bladder. After his treatment they are recommending a radical cystectomy, which they told him means removing his bladder, part of his small intestine and part of his prostate. He has Crohn's and he's worried this will make his Crohn's worse. The doctor's he's spoken to are more concerned about removing the cancer than his Crohn's. He has spoken to his oncologist about his worries, and was told this was the "best successful treatment out there". He meets the surgeon on April 11th. Is there anyone out there that has gone through what he's going through that can offer some advice on what they did/went through. What he should ask the surgeon? Anything can help...please. I'm an only child and my parents are everything to me and I want to help him anyway I can.
Signed,
Jennifer-A scared/concerned daughter