Haven't you considered visiting the doctor for the treatment of your father? It will be great help from the doctors as they can suggest some best options for treating bladder cancer.
So make an appointment with the specialist ASAP and get your father treated immediately.
Well, as per the treatment there are a lot of treatment options available in the market including surgery, chemotherapy, radiotherapy & Immunotherapy, etc. You can discuss with the doctor which will be best for him and which medicine will suit him.
Best wishes!