If you were to combine several of the units together to the point there are only 5 units in the building, would this destabilize the whole building and be able to bring the rents up to market rates once the leases laps? 

I've seen lenders exempt years spent in college as "work history" but the borrower would still need to have sufficient funds/reserves and a solid credit score. 

In the meantime use this resource to find out the areas around hereUse this rating and classification system I have created over time to get an idea of the "Class" for the area - A class B class & so onhttps://www.areavibes.com/Here is my rating & classification for each livability score. 80 and above A+78/79 A76/77 A-74/75 B+72/73 B70/71 B-68/69 C+66/67 C64/65 C-60/63 D59 and below F

Aside from the higher interest rate (I will pay the mortgage), one of the areas I'm looking in charges higher property taxes if it's not a primary residence.

In your case, where your rental rate is $2300 for a 3-bedroom unit and the maximum voucher amount is $1650 per month according to local resources, there's a notable gap.

Rents do go up over time (as do costs, but hopefully at a lower rate). 

He owes 43K to the bank at a 11% rate of interest. 

I also know that my apt complex is in a Turkish Fund for an investor.      

What are the terms (payment amount, interest rate, duration, etc.) of the existing financing?

Credit history and sourcing funds for down payment / closing will be a factor in the pricing of the loan.