Unfortunately, as you have surmised, this is not good news at all - once prostate cancer has metastasized into the bones, it’s not curable. However, there are now a number of new
drugs (as well as
hormone therapy) that can kind of keep the
cancer at bay for awhile. Only his Dr can tell you what his prognosis is, and if he sounds kinda vague about it, that’s cause it’s very hard to predict how a patient responds to treatment.