can't say. was the family member the one that rented the property? if so, was the property rented at less than Fair Market Value. What's the FMV of the property vs the mortgage.
if the FMV is more than the mortgage you have made a gift that besides creating tax issues for both of you may require you to file a gift tax return. see this link for a further discussion.
https://www.nolo.com/legal-encyclopedia/irs-rules-real-property-sales-relatives.html
