Except in the nine community property states, surviving spouses don't inherit responsibility for their partner's debts. It would typically have no bearing on a decedent's auto lease if he was single or married, assuming the lease is in his sole name. If he dies before the lease expires, however, someone has to pay the associated debt.
Early Termination
When a car lease is in only one person's name, his death can trigger early termination of the lease. If the vehicle is returned to the dealership due to his death and before the lease expires, early termination fees and other penalties would typically come due. The leasing agent will most likely sell the vehicle, possibly for less than is still owed on the lease, and this difference can add to the overall debt.
Responsibility for the Debt
Technically, the deceased's estate is responsible for paying off the lease. His executor would most likely turn the car in and pay off the debt with other estate assets, such as life insurance proceeds. Another option is for a family member or heir to assume the lease on the car and avoid the unnecessary extra fees associated with terminating the lease early. The heir could take over the payments and drive the car for the remainder of the lease term, although his credit would have to pass muster with the leasing company just as if he had gone out and applied for a new auto lease of his own.