Would he qualify for a HELOC if he put the money towards principal, and is he disciplined enough not to use it for frivolous things? What's the rate/term/payment/years remaining on the mortgage, what's his average monthly income, should we expect it to stay the same in the future for planning purposes, and if not what's a good estimate? (Or, to put it a different way, what's the maximum average monthly payment we could expect him to be able to handle from income?). Is he current on his mortgage, and if not, how far behind is he?