Treatment should be carefully considered and ideally in a multi-disciplinary setting with urology, radiation oncology, and medical oncology. It is not clear to me whether he has had full staging evaluation - are there any pelvic lymphadenopathy (stage IIIA could be based on cT3-T4a or cN1 status), any evidence of distant metastasis? He is a poor candidate for surgery, but would chemoradiotherapy or radiotherapy alone be an option? With regards to systemic therapy, he is clearly not a chemotherapy candidate. I would also be hesitant about offering immunotherapy with his baseline polyarteritis nodosa that increases the risks of immunotherapy-associated toxicities, and the questionable risk/benefit expectations at present. Since he has already undergone a TURBT, it may be most prudent to monitor and reassess the tumor status (cystoscopy and chest/abdomen/pelvis imaging) in 3 months. If there is persistent/recurrent disease, then either repeat TURBT or systemic therapy may be considered. You could send tumor molecular testing for FGFR alterations in the meantime, in case there is an FGFR alteration targetable by erdafitinib. Immunotherapy may be considered at that point after a careful discussion about possible risks/benefits. Enfortumab vedotin (with dose reduction) could be an alternative option.