Looking for advice

First off take an big breath. The stress you are under is intense right now as it is on your boyfriend. First off non invasive bladder cancer has a high rate of reacurrance but a reacurrance is not the end of the world. The places he tumors that came back were probably seeded and ready to grow when the last TURBT was done. The thing with non invasive is keeping a check on it and making sure it does not become invasive.
A lot of people have trouble with a catheter but he have to remember that it is for a small amount of time. They do not always have to use a catheter following TURBT it depends on how much has to be done. There are ways to make the catheter more comfortable during BCG please talk to your urologist they can use a numbing jell and also can give your boyfriend something for nerves prior.
If your boyfriend is having trouble with drug abuse he will need to be willing to seek help. His anger at you is probably his anger at the situation and his own inability to handle his own fear. But he has to be willing to seek help before things will get better. Some of what you have said makes me believe that he may not really understand bladder cancer. Some people hear cancer and think it is a death sentence and that is not the case with non invasive at all. Non Invasive bladder properly treated just become a fact of life for most survivors just like any condition such as diabetes or high blood pressure. Let untreated all three can have a bad outcome but with proper treatment life goes on. He has to understand that if he does not seek treatment and keep this in check that the discomfort of this will seem small once his choices are out of his hands.
If your boyfriend will not talk to you is there someone he trust that could talk to him? How about having him post here we will be happy to listen and share experiences? We all understand that being told you have cancer is a shock we have been there done that. Anger and depression can be a very normal reaction for some. I really think if he understood his diognisis better it might help with the stress. Many of us have found that we needed therapy or marriage counseling after our diagnosis but he has to be willing.
Nothing breaks my heart more than seeing someone die because they could not pull themselves together and fight when they are dealing with a situation that could have had a very different outcome. Hopefully he will get to the place he is in and reach for the help he needs to move forward he has a lot to live for.
Hang in there we are here for you.