Not a lot of cons to irrigation other than the time commitment. I now have an ileostomy after my third colon cancer over 35 years. I started irrigation in 1989 and didn't realize how many issues and problems I skipped over the years until I got on some of the stoma/ostomy/irrigation sites on Facebook. I now know some people can't irrigate for various reasons (part of which I believe is Dr. Stomas Nurse's lack of understanding), but your options are to walk around with a 1/4 - 1/2 bag of poop in a bag or rinse out your colon every 36-48 hours and walk around with an empty bag (p.s. an empty bag doesn't leak). I irrigated every other night and ran a tire store, then sold my store and went through real estate school and worked as a real estate broker for 33 years. Without irrigating, I don't believe I could have done that.
Taking the time can be aggravating at times but is well worth it. I set up a chair in my bathroom and a TV and would watch a program while I irrigated (low stress is good while irrigating). I have gone to sleep while irrigating more than once. I wasn't too worried about timing; sometimes it would be early evening or late at night. If I ate too much, I sometimes irrigated extra (maybe 24 hours instead of 48 hours), and occasionally I might get an unexpected deposit in my bag, but it was never a big issue and it was rare.
This doesn't sound like an optional surgery; his stoma and bag are saving his life. He will learn to control his stoma and not let his stoma control him (or his family).
Tell him I said congratulations on getting his extension to life; make the best of it.
He's lucky to have a wife that is as helpful as you are and lucky that his cancer is in an organ that can be cut up or even removed, and he can walk out of the hospital. Cancer's not that nice to lots of people.
I'm off my soapbox now! Good luck.