Umm, what? Friend or not, if your name is on the title (with no lien) then they can't tow it. If your name isn't on the title then attempts to move or hide it, are questionable.
If what you wrote is true then you need to establish your ownership asap and get it retitled in your name, but playing devil's advocate you could hide it or stand guard and refuse entry onto your property. A repo/etc can happen if you aren't present to tell them to stay off your property, but can't if you tell them to do so.
With no key you need the VIN to get a key cut at a dealership and they will program it. You can get a new cylinder and key cut to match at a locksmith if they have the programmer to get a new key accepted by the vehicle.
This is a strange, rare, situation, especially the short time frame of until morning to resolve it. Why would his suicide result in his vehicle being towed away the next morning?
Something is fishy.
