I have a lease due, one of my old employees has been driving my lease since February, and been making the monthly payments. He want to my the truck now, what is the proses for him the pay the over mile and any damage to my the truck himself

There would have been an amount set in your original lease agreement for what he purchase price at the end would be. Look at your paperwork or contact the dealer. They will know.

If this is a Retail Lease you need to get with the Dealership and discuss the purchase options. if you buy the vehicle at the lease end generally there is no mileage or other penalties but you will need to discuss with the dealership and lease company.