Rent back Agreement After Selling House

[Geoffrey Jones]

Hey guys I have a deal that i'm analyzing need some help to see if I should proceed on it.

Owner is in the middle of a lawsuit case. They are anticipated to receive some money in excess of 3 million. 

Property value: $900000

Current Mortgage: $0 (They own free and clear)

No repairs to be made. Property is fully updated and modern.

They are willing to sell the property to me for $600000 on a condition that they stay in the property for 3 years with rent paid upfront for the full 3 years, with a buy back agreement of $900000 or estimated property value after the case closes. 

If the case closes for less than the 900000 they will agree to move out and not buy the property.

Rent in the area goes for about $10000+/month and they are willing to pay it upfront as I am assuming the risk.

Property is in an really great area.

Do you guys think this is a good deal?  How would you structure it and what forms would you use to do this?

They have owned the house for 20+ years so they have some obligation to keep the property in good condition as well. 

Let me know your thoughts.