Yeah there is ZERO chance he willingly drops out. Getting re-elected is his only path out of the hole he keeps digging deeper. Well that or leaving the country for good and living out his days in Russia.
Eh, he'd probably set Trump up in a gilded cage and forget about him. It'd be a short stay because Trump is old, eats McDonalds, and doesn't exercise. Only the McDonalds part would change because they don't operate in Russia anymore.