As highly amusing as it would be it's extremely, extremely unlikely a former POTUS actually ends up behind bars. But here's what Trump really has to worry about - he has at least $900 million in loans coming due in the next 4 years. He's also engaged in a battle with the IRS, and an adverse ruling could cost him another $100 million. $300 million in personally guaranteed loans are coming due fairly soon.
Trump is involved in over a dozen civil and criminal suits right now, which are likely to be extremely costly. And after what he's done to Rudy, stiffing the schmuck, who is he going to get to help him? He no longer has the office of the presidency to protect him or dangle pardons to sycophants and his most valuable real estate assets may very well go bye bye when he can't pay his debts. You can't circle the drain forever. Turd is gonna get flushed.