Okay - you are probably not going to like this but:
- my father-in-law was diagnosed at the age of 79 and wished he had never known - he felt that it spoilt his last years
- it seems unusual not to bother with the biopsy so perhaps other information has convinced them that it is PCa
- for example, it may be that the urologist could feel the cancer when he did a DRE - but you may not be able to ask your dad whether he had a DRE :-/
- it is entirely possible that dad decided not to give consent for the biopsy
- would your dad agree to put in writing that the doctors can share information with you? If so, you can ask the GP and urologist for more info without dad having to get flustered about it all
- if there is a reason why they are convinced enough to put him on HT, fair enough - but if they are just guessing, I would push for no treatment until / unless there is a diagnosis