Hi Norma, @ojosverde, You must be so worried about your son. Let me start by spelling out the acronyms
SBRT = Stereotactic body radiotherapy
Here's more information about it from Mayo Clinic https://www.mayoclinic.org/tests-procedures/sbrt/pyc-20446794

PRT or PBRT = Proton beam radiation therapy (or Proton therapy)
https://www.mayoclinic.org/tests-procedures/proton-therapy/about/pac-20384758
Lupron is a type of hormone therapy used to treat prostate cancer that is fueled by testosterone.

What treatment is being suggested for your son? How is he doing?

ojosverde,
sorry about your son's cancer. Cancer treatments are never easy.
Stereotactic in SBRT means the tip of a beam of radiation is directed in three planes using medical imaging to locate the precise location of the lesion. Because the location is precise less damage is done to surrounding tissue.
Proton in PRT is a different part of the atom. Primarily radiation therapy uses photons. The advantage of proton is that they can direct the strongest part of the beam into the tumor.
There is no exit damage from the beam. You still have entrance damage. And there may be equal, more, or less damage to the tissue at the sides of the beam. Controversy surrounds the advantage of either.
Lupron is an anti testosterone medication that slows the progression of tumors and slows metastasis. Orgovyx is a newer testosterone inhibitor said to start inhibition sooner and without the flares attributed to Lupron. Lupron is by injection. Orgovyx is oral.
Side effects are unpleasant. The most worrisome is depression. It is important to be gentle and not take personally any behaviors (especially verbal) during administration of this class of drug.
If you son has not had genetic testing (somatic) of the tumor itself. He might ask for Decipher. It can help with treatment options by indicating prognosis. He could also have familial genetic testing. It may be inherited with BRCA genes.
The radiation treatments are the easy part.
I had proton for GI cancer five years ago at California Proton. Carl Rossi has probably the most experience with the treatment because that is the cancer he treats. The treatment is painless.
Aftercare for cancer is not great. I had to fight for each pet/ct thereafter. After care for prostate cancer is better because it is more easily detected through PSA. I hope your son takes advantage of rehabilitation programs and mental health programs. They are especially important with prostate cancer.
Bless you and best wishes for your son's health