Unfortunately the major lenders and captive financing arms need to adhere to general guidelines where they have to treat everyone the same. They cannot make special exceptions for people, because someone else later could claim how those one off edge cases were biased toward a protected class or borrowing class. Having dementia is not sufficient for MBFS to provide a different option or subvention for your father to exit his closed end lease.
If you haven’t done so already, it seems you need to get some form of Letter of Administration or some Power of Attorney to act on your father’s behalf. You won’t be able to accomplish any complicated transaction or discuss financial matters on his behalf without some formal documentation or court granting you those powers. Your or your family will want to speak with someone to get that process going.
Specific to the E450… the lease early-buyout is your best bet, but will likely cost you some money to execute. Do you know the lease buyout amount right now? You should be able to download a payoff statement or something from the MBFS portal. Or it may even be shown on the most recent paper statement if your father still gets paper statements.
Just using some fuzzy math here but let’s say the buyout is $60,000 on a RWD E450 Cabrio.
Next you’ll want to get quotes to see what the car may be worth if you sold it through some of these options.
Remember, those companies will want to make margin flipping the vehicle for profit. So they won’t offer a full retail price. But, they do get you a reasonable estimate for what cash you could get if you sold a car to them. Let’s say the best offer is from Carvana at $55,000.
At this point, to exit the lease you would need $5k of your own cash. Then ask them to buy out the $60k from MBFS with Carvana’s $55k + your $5k. There may be some other fees or taxes involved, so you’ll still want to have a call with MBFS to make sure everything lines up for you.
If you instead wanted to sell the vehicle to someone yourself, that’s an option too. But it’s quite a bit of legwork and of course then you’re spending a lot of time and prep to manage listings, clean up the car, take photos, get inundated with spam mails from shady (non LH) brokers, and will suffer dozens of messages from lowballers.