Seller credit / equity gift

[Ori Mo]

Hi, 

I wonder if someone can give me an advise of how better to approach a deal, I'm looking to buy a 2 family house in NY for 600k, with 20% down and 80% mortgage, the seller agreed to give me 60k as seller credit or equity gift toward the down-payment so he will get 540k, The seller is not my relative, can I do it to help me with the down payment? Which way is better to go with? 

The property will apprise for 600k no problem. 

Thank you