When tenants in common cannot agree on the future of the shared property, a court must decide. If the court decides said property should be sold, who pays the real estate agent? In the current state of this market, this property is worth not much more than what it was purchased for. In, this situation, there are 2 names on the title but only one of them is the mortgager. Are both required as homeowners to foot the bill for sale?
Whoever is on title would be considered the seller.
The cost of the real estate agent and other costs of sale should be shared by the tenants in common, most likely in proportion to their ownership interest. The fact that one of the tenants has mortgaged his/her share is not a factor. Best of success.