First, if you are concerned about a potential language barrier, is it possible for you to go to the appointment with your parents'? You could help them to understand their options.
Before I go any further, I want to be clear that I am not an MD and that I am not giving medical advice. I am trained as a cancer biologist and come from a research background, so I do understand some of the terminology and treatment options available. You really should sit down with you Dad and his oncologist and talk about these issues.
Stage II bladder cancer is invasive into the surrounding muscle of the bladder. Here is a good site with fairly easy to understand information (
http://patient.cancerconsultants.com/CancerTreatment_Bladder_Cancer.aspx?LinkId=53848). Standard treatment for stage II is radical cystectomy, or complete removal of the bladder and surrounding muscles and tissue. If his cancer is still considered stage II, it is still considered treatable with surgery and chemotherapy. since you mentioned that his bladder cannot be removed due to his weight, that may be why the oncologists are being dire. Once again, I would suggest you speak with them.
If the uro-oncologists have evidence that his cancer has spread to his lymph nodes, his cancer will be considered stage III/IV. This is now considered metastatic, even if metastases have not yet been found.
I do not know if I have helped you in any way. Cancer is an absolutely dreadful disease that affects virtually everyone. I am very sorry that you are going through this. If you would like to ask me direct questions, send me a PM.
Tracy