Can a Buyer Prevent a FSBO from Refinancing a Mortgage on the Property That He Has Under a Land Cont?

refinancing

Looking to buy a property from a FSBO under a land contract that has an existing 3% equity line of credit mortgage, is there any way we can write the contract to prevent him from going behind our back and renewing the home equity line and or obtaining a new mortgage on the property, we are filing the Land contract at the district recorders office