If she is on the mortgage, she is likely on the deed too.
Now ain't the best time to sell in Calgary(I assume)
Don't be in a rush. Make the payments and call it an investment for now.
They should be splitting the payments, and then since he is living there, he should be paying a fair rent for the place.
Kinda offsets her payments as she isn't living there.
Rushing is only going to cost extra money.
Give it a year or so for things to come around, unless they can make money on it now.