So sorry to hear that you have joined us, but welcome anyway!
There is a lot of information on BCG in this forum...just "search" for it. But to answer your question about the side effects, BCG is an attenuated tuberculosis bacteriium and its purpose is to cause an immune response in the lining of the bladder which will also fight the cancer. It is especially helpful in the case of CIS (which I also had). CIS is high grade, as you mentioned, and it is important to get rid of it asap.
The side effects usually start out with mild fatigue. The first few hours after the instillation there is urgency and burning and sometimes bleeding with urination. These side effects become more pronounced with time. And this is what you want....it indicates that the immune reaction is what is should be. It is a bit uncomfortable, but usually only lasts a day or so. It is much less unpleasant than traditional chemotherapy.
I would suspect (I am NOT a doctor) that your husband's urgency problems are due to the CIS!! After several BCG treatments, mine practically disappeared. I was told, after instillation, to hold it as long as possible, with 2 hours being a goal, but not to despair if I didn't make it. Perhaps your husband can arrange to lie down at the doctor's office immediately after the treatment. This should help him to hold it as long as possible...rather than trying to walk around or drive home!
It is certainly worth trying to have the BCG treatments. If they work, it would be MUCH preferable to having the bladder removed. I was able to have the complete series of BCG (6 times, once a week) and then the maintenance series (every three months, once a week for three weeks)for two years.. If the side effects become too bothersome, it is possible for the dose to be lowered. I was on 1/3 the initial dose by the end, and it is possible to go even lower and still be effective.
This article gives a pretty good overview of BCG
emedicine.medscape.com/article/1950803-overview
Remember when reading about the side effects, that they ALWAYS mention everything....and these are all unlikely to happen to one patient!!
In summary, BCG is very do-able and can truly help in cases of CIS.
Sara Anne