I would agree with Dan that in the US, this might be treated differently, so you need to see if you can get US medical type treatment in rural India.
In the US you might be talking to a urologist about surgery, a radiation oncologist about radiation, and a medical oncologist or urologist about hormone therapy.
It is generally assumed in the US that there is no one right way to treat this disease. So if possible, you would seek out different doctors with different disciplines that would treat the disease differently, and the patient would make a decision on what treatment to get.
Also many men in the US use diet and supplements to treat the disease or as an adjunct to any mainstream medicine.
In your father’s case, how the disease is treated by mainstream medicine would depend on a couple of other pieces of information that would give further clues as to the extent of disease and the aggressiveness of the disease.
1. What percent of the cancer is grade 4 vs. grade 3?
2. What is his psa and what is his psa doubling time?
3. What is the cause of the swollen lymph nodes?
4. What is the cause of the back and thigh pain?
Also a bone scan is relatively insensitive and for bones doctors are starting to use the NaF Pet Scan as a more sensitive bone scan.
Dan is right in that hormone therapy is not a cure. It is also very hard for some men to deal with the side effects.
If your father ends up on hormone therapy, some doctors in the US will do the LHRH agonist monthly like you are doing, they would add bicalutamide continuously not just for 10 days, and they might add a 5 alpha reductase inhibitor, so your father would be on 3 drugs, not one.
If you father ends up on hormone therapy, also talk to your doctor about intermittent hormonal therapy.
This is probably a lot and do not wish to overwhelm you, but your best bet might be to find a doctor that is willing to work with you to come up with the best options.
Gene