Welcome, although sorry that you need to be here!
Yes, it is possible that this is a totally normal event after the TURB. Small pieces of the bladder lining and muscle were removed during this procedure and scabs formed over the wounds. If one falls off it is possible for the bleeding that your husband noticed to occur. However, he should mention it to his doctor (probably the most efficient way to do this is to leave a message for him with his nurse.) While we may have a pretty good idea of what might be going on, we are NOT doctors here!!
Good luck to your husband!!
Sara Anne