Mortgage payments to whom? If a lender has a lien on the property then you need to review the lending document regarding its
If the church owned the property, the pastor should have been taxed on the FMV of the parsonage.
The fact he paid the "mortgage payments" is completely irrelevant unless the mortgage payments constituted his parsonage.
At very minimum, you need to review the church's by-laws with respect to transferability of its property, and obtain an appraisal
of the home for valuation purposes.
You are not disclosing a number of material facts that are necessary to provide you a reliable answer.
I strongly suggest you obtain legal counsel regarding this transfer.