Pull together all paperwork. Good likelihood that there may be an escape clause. If your husband had anything else in his name at time of his death, that, too, may be within his estate. You may wish to consult with a lawyer on this; I would NOT rush to make any payments. Make sure, of course, that you do have a copy of the Certificate of Death. Look at payments and see if there is any additional premium or assessment for insurance on the contract.
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It sounds to me like you would prefer to keep the lease going on the vehicle. While technically, the lease contract was between the dealer and your husband, the practical truth is that they want the money; and they won't rock the boat if you don't.
I'm not advising you to conceal anything. I'm not giving you any advice at all. I'm just sharing my thoughts to give you a moment to see your situation from a different angle.