My DH has had a urostomy since 1992 as a result of having his bladder removed from cancer.
He met with the ostomy nurse prior to his surgery for his "marking" and then after the surgery. Back then he was in the hospital for 2 weeks. I don't know how long they keep you in these days.
In DH's favor was a H.S. friend of mine who worked at our neighborhood pharmacy who was a true life saver. Osteomy care and products was his specialty. DH continues to have the occasional accident but there are times it can't be help.
For those who take showering for granted, be grateful you don't have to do the prep involved with taking a shower and afterward. You deal with skin prep and special tape, osteomy bags, all of which cause skin breakdown.
However, DH is grateful he is alive, beat cancer and is the grateful recipient of a kidney transplant.
O.P. Help is out there and this should have been explained to you before your brother left the hospital.