I had bladder cancer a couple of years ago. My baldder was removed but I was lucky and instead of a bag the doctors reconstructed a bladder inside my body. Sometimes they can and sometimes they can not. Your dad should check with his doctor. I had my surgery done at USC in California. I live in Texas
Your dad should be OK. It has been 2 years for me and I thank G_D every day. They have made tremendous headway in detection and treatment.
I also have a friend in his late 60's who had his bladder removed a few months ago and has a bag. He lives a very happy life and does everyhting swims, hikes etc.
I don't think i can provide my personal data in the forum but I am willing to talk to your dad by email or phone if it helps him. I had a lot of people helping me and it was great to have someone to talk to that had gone through what I was going to go through.
He is going to need support, patience and pushing.
Luis