What _should_ happen is that the cardinals should get together and reign him in, with the implied threat that he can be found to have lost his office by heresy. (There is significant evidence for that.)
He will be out of the picture before too much longer anyway ... the old-fashioned way.
The Vatican II Council itself was arguably schism, led by heretic antipopes!
“Put that in your pipe and smoke it” as the old saying goes.
(In that light who IS Mueller but one schismatic criticizing another!?)