jks,
Hi,
If I were this fellow, a third opinion from another oncologist would be mandatory. By the way, I assume both physicians he went to were oncologists? Not all prostate enlargements or tumors are cancerous; though, most probably will be. And, you do not say what the "other something going on" is. As for feeling better after getting off meds for cancer? Who would be surprised by this? :)
Should you have said that you didn't feel it was cancer? Speaking only for myself, no. Unless.....he had asked what you felt. Then one is free to say or not say. Remember, Reiki practices are not for diagnosing medical conditions.
Cheers,
RC