@Gwen Fyfe an offhand verbal remark doesn’t constitute a legally binding contract, especially in real estate.

I think you're going to be hard pressed to find this on a non multi-family building, but that additional information may help to provide some additional guidance.

The issue with that plan is that the FHA max financing is 75% LTV when using a non occupant coborrower for a multifamily.Best option would be to try to qualify him on his own.

Yep, this is definitely for people that will buy as a primary residence (not investment/non-owner occupied). 

If not, where can I get legit comps as a non-agent investor? 

You can 1031 exchange if you like into non residential (commercial or NNN etc). 

I can't count the number of foreclosure sales I've attended that had short sales under agreement, short sale approved, just waiting to close and the bank slammed the door on it with a foreclosure.Because MA is a non-judicial foreclosure state and the banks are not required to disclose anything about the pending foreclosure, other than the public notice, it's nearly impossible for a short sale agent to know the status of a foreclosure and how much time they've got to get the deal done.

if private money forecloses due to non payment... forgive my naivety. 

If using a lender this is a non issue.

NO verbalization.