1: Age in itself no but other health issues or ability to tolerate some treatments might in the future. The present treatment of HT (hormone therapy) is standard in such cases as your dads.
2: not unusual to have no symptoms. However as we age some PCa symptoms such as increased frequency of water works might have been put down to just age.
3: Generally PCa is slow growing. Learning to take one step at a time is a good way forward. The first step is response to hormone therapy. Nothing you have said suggests it will not be a good response