Hello Labs and welcome from me too.
Since dad has already been diagnosed and treatment started you might benefit from looking at The Toolkit from Publications in this site.
There will be a section on Hormone Therapy among others and it will help you understand how is likely to be feeling. HT can make some men emotional, especially in the early stages of diagnosis and then treatment.
It's scary for the PC man and just as scary for his family.
As Steve says, feel free to ask questions, or come on and have rant when it all gets too much.
If dad will let you go to appointments with him that may be a good idea because there is so much information to take in. Get him to write down his questions and if there is somebody with him they could also write down the answers.
If you know what dad's PSA and Gleason scores/Grading were it might help with advice.
Best Wishes
Sandra