Trish,
The biopsy material can be sent to another pathologist (ideally a large, cancer specific institution) for a second opinion. It is the pathologist, not the treating doctor who determines the grade and stage. A second biopsy read MAY help sort things out. Your insurance may be able to help coordinate a second biopsy review - but demand a bladder cancer specialist enter do the second reading.
As I read your comments, there is no muscle layer in the biopsy. Without finding disease-free muscle (or wide, clear margins) under a tumor, muscle invasive cannot be ruled out. Do note that micro invasion is possible even with a clean muscle sample. You mention "nests" in the biopsy report - there are a variety of nesting presentations, and the type of nesting can be important in determining treatment.
Since you are clearly a web researcher, I suggest two sites be reviewed. The first is my go-to first source for information that relates to ME. You will need to compare your situation with the presentations. Caution - only a treating doctor can (or should) be able to explain your situation, the objective findings AND the options available along with the risks and benefits of each.
The second article is based on much of the same information as the first, but is a good check on the conclusions that can be reached by a different group of researchers.
A second opinion as a necessity when there is any doubt or confusion. If questions are not answered is a straight forward manner, it is time to find a new treater; this is especially true if the current treater is a general practice urologist with the typical limited treatment options.
Expert consensus document: Consensus statement on best practice management regarding the use of intravesical immunotherapy with BCG for bladder cancer
www.nature.com/nrurol/journal/v12/n4/full/nrurol.2015.58.html
Consensus NMIBC American Urological Assn 2015
It can be a scary time for your husband. He may feel safe with his current doctor and wish to avoid changing doctors. It can be a rough time; the two of you need to be a team battling the disease that is affecting both of you.
Best,
Jack