monthly mortgage payment. If there is the ability to make the mortgage payment monthly and stay current on the loan, then it doesn't matter what state law says. The bank will continue to allow the family to do this indefinitely until you sell the property.
On the other hand, if you don't make the required mortgage payments, then you get into a state law issue of whether or not there is a moratorium, and how long that period is. 6 months is fairly common, but I know of at least one state where there is none at all.