Merely owning real estate or property does not automatically cause one to be obligated under the mortgage that encumbers said property. To be liable under the note and mortgage, one must sign the note and grant the mortgage in the property.
However, if the note and mortgage is in default, the creditor is permitted to foreclose on the property. In the situation described here, the property could be sold — but the owner who did not sign the note and mortgage would not be responsible for any money due under the note.
There may be an issue of whether the entire property is subject to the foreclosure, or whether just the one-half interest of the owner who signed the note and mortgage can be sold, depending on the timing of the mortgage and transfer of the property. You may wish to consult an attorney regarding this issue; you can find a local attorney for FREE at Standard Legal’s Attorney Find page.
Again, the owner who did not sign the note and mortgage will not be obligated to pay the creditor.