From what I know, most prostate cancers spread very slowly.
They say your age is the percentage chance you have prostate cancer. For example if you are 75 years old, there is 75% chance you have prostate cancer. Good news is old age will kill you before the cancer. However there are a few types of prostate cancers which metastasize faster. So always get PSA test done every year after age 50.
His cancer is not the slow “watch & wait” variety. He’s also ‘young’ & this one will kill him before he dies of old age if he does nothing.