The average lifespan after metastatic bone cancer has been diagnosed, is about 9 months, and that's assuming that you have a fairly healthy person (aside from the cancer).
Joe is anything but healthy. There's more than a fair chance that he won't make it to summertime.
They'll probably start with androgen deprivation therapy, and do whatever they can to make him as comfortable as possible, but there is no cure.
I highly doubt they'll try the more promising experimental treatments, since those are supposed to be used in combination with radiation therapy, since drugs such as RK-33 sensitize cancerous cells and make them more easily killed by radiation.
Any dose of radiation therapy would probably kill him off quickly. If he didn't expire right afterwards, whatever tiny remnants of his immune system would be gone, and he'd die from a common cold or whatever is out there.