Tenant has bought home, another 4 months left on lease

[Elizabeth J Humphrey]

My tenant has informed me that he has bought a home and will be closing on the home in early Oct. and plans on moving out that month. That leaves 4 months left on his lease. He has said he will honor the remainder of the lease, but would like to be absolved of any liability from the property and would like to have the utilities transferred back in my name. I would like to have him sign a new contract that states he is responsible for paying the remainder of the lease until a new tenant signs a lease and/or we sell the property. We are considering selling the property as this is our primary residence up until this past March and is about an hour away. How to word the new contract? Do we need to add the fact the property may be sold? What kind of recourse do I have if he does not hold up his part of the contract? I realize what tenant say and what they do can be different, but this tenant has been very honest and most definitely paid on time. Does anyone have some sort of contract that addresses this issue? Thanks in advance.