Paying seller over 2-3 years (so he won't lose his food stamps)

[Nat C.]

Firstly, I'm not asking for legal advice, so any replies don't need a disclaimer :)

A seller I'm buying a house from is concerned about becoming ineligible for food stamps and Medicaid when I buy the second property on his land due to receipt of a large sum of cash.

I'm paying 30K to him and 30K to his sister. He asked if there was a way I could pay him $1000 a month over an extended period instead of all upfront so he could keep his benefits. Can an uncomplicated contract be written up for an arrangement like this?