@Bradley Bogdan Good point but I'm going to reveal something about the MLS.

I've offered to pay his closing costs to get his own fresh mortgage but he says he is fine with what we have in place.

Evidence presented during trial revealed that from May 17, 2005, until February 21, 2008, twenty individuals, under the direction of Robert Brooks, participated in a mortgage fraud scheme where Brooks purchased properties at fair market value then resold at an artificially inflated price to straw purchasers.

Other studies reveal the number of people in the workforce is continuing to decline.

The lender gets a fresh borrower with better capacity to pay.

(My locksmith had to settle for a bottled Margarita which, as we all know, is not worth consuming unless it is made fresh.)

Enough that I actually drove by that lot: As vacant as can be, not even weeds have grown on the fresh dirt yet, and the hood rats haven'thad the chance to rip off the yellow barrier tape yet....My point?

Using an online calculator will reveal that price to be way out of reach.Also, going to a lender will lead to a similar estimate unless OP seeks a mortgage pre-approval which could lead to a hard pull on her credit. 

But if you're just concerned about his honesty in general and/or that he may be taking shortcuts with the rehab on the one house you're buying from him, you should be having an inspection done that would reveal any issues as far as that goes.   

@Olim Toiriyon in this current market, i would take advantage of the opportunity to potentailly increase rent, undate the place and seek a new fresh tenant.