The fact that the lymph nodes were positive for the presence of cancer indicates the possibility that the cancer might have spread further. Chemotherapy following cystectomy for this reason is the "standard of care" in such cases.
If your father-in-law is in good health otherwise and this is what the doctors recommend it would be foolish not to do it. The whole purpose of removing the bladder is to get rid of the cancer. It would be a shame to stop before the job is done.
Diagnosis 2-08 Small papillary TCC; CIS
BCG; BCG maintenance
Vice-President, American Bladder Cancer Society