Can you cancel Contract to Sell home

[Alex Szymkowski]

My fiancee's uncle is selling his home in New Jersey and moving to Florida. He has got a estimate from the realtor for 600-634k. It's a 2 family home and Comps are 500-600k in the area.

Long story short I want to buy the house as an investment property for 530-560k sold by owner. So he saves 4% on real estate comission and gives me a lower price. He said he setup a contract to list the house (open house) this August 2021 for 6 months. Can he back out of the contract with real estate? Or do we have to wait till the 6 months pass?