2 Family Sub2

Well I met with this landlord selling 2 places. He only wants to deal with 1 now becaue the renters may be buying the other. The place he wants to sell is a 2 family. Its a typical 90 year old place in these parts. Not a pretty house, but structurally sound. Bottom rents out for $500. Top is vacant but rented for $425 recently. He sort of likes the idea of sub2 but has concerns. He wants to know that I wont let the renters trash the place, and then give him the house back destroyed. And also the usual, how do I know you'll pay. All in all though he sounded like he will sell it this way. Here are the #s. FMV as is: $66,000 Owed in 1st mortgage: $61,000 P&I: $325 Interest: 3.75% Taxes: $1700 a year Insurance: $375 a year Utilities: $200 a month I know this is skinny for a straight rental. I did consider lease option though I dont know how that would work on a 2 family. Any thoughts on if I should pursue. I think its up to me now on whether I should start verifying numbers or just pass.