My spouse has no drivers license and is deeply in debt. He is calling car dealers. I gave his car to our son when we took his drivers license away. My spouse calls our son every two or three days wanting his car back. Now he is asking the son for a payment for the car so that he can use it for a down payment on new car. We have tried telling him he can't drive anymore because of health reasons. (He has copd and is on oxygen 24/7 and has cognative disorder).
Another possibility if he tells you he's going to a specific dealership to look for cars is to alert them that he has no driver's license and no money (the latter statement should be or more concern to them!).
However, one unsavory character insisted he would bring a photo of the vehicle about which I had called to my house. I insisted he wouldn't! I was uncomfortable for a few days wondering if he would back trace my phone number and show up at my front door.
This is a rough time for your husband. Loss of independence is a serious challenge, and losing a car and being dependent on someone else can be a major shock.
Can you plan some outings for him just to show that you or your son are available to take him and he doesn't need to be afraid of being stranded at home? Make it a nice family outing so he can relax.
My father eventually said he got used to someone else doing all the driving work and that he could watch the scenery more leisurely and comfortably than he could when he was driving.