BOT cancer, in the opinion of this non doctor, should be approached with radiation and concurrent chemo before any surgical considerations are in play. A surgical solution to this location can leave him with significant quality of life issues for the duration. Please see that he explores this with a radiation oncologist before moving forward in any other direction.
Welcome to the board, and a group of people I am sure will take good care of your concerns and issues as you and your father move through the treatment process.