legal rights of a person in prison to property owned before going to prison

My father-in-law and his brother purchased a house for their mother a while back. The deed says that the property is held as a joint tenancy with the right of survivorship to each respectfully. The problem here is that one of them is now in prison and will not be out for some time. Their mother has since moved out, so is the property the sole possesion of the other, or is there still a joint tenancy? Can you please answer this question with Georgia real estate law in mind?

Thank you.

Don't know Georgia law, but if it is ike laws elsewhere, the property is still owned in joint tenancy as long as the guy lives (unless he deeds his share to a third party or breaks the joint tenancy).