Top decile probability of death is 55 % over a decade or roughly 0.5 % per month. Thus, biden has 1 month to croak and trumpo has a year to croak, which leads to (1-0.995)*0.95+0.995=...=0.025% chance or 1 in 4000 for both to occur.
https://www.soa.org/resources/research-reports/2020/us-mort-rate-socioeconomic/
(the website data is more interesting than low probability of success)
It can still happen but in a different way. Carter could die at any moment. Bill is in the hospital. We've got a few days left for Biden to stumble his way to death and Trump to get shot. Year of 4 dead presidents is also something
Hahaha yeah I did