Impeachment, and not of the cabinet, but of Trump, could be the ticket. It's not necessary to have a 2/3 of the Senate conviction. Here's the scenario:

Signs of Trump's dementia (just listen to the monotone weirdness of his Davos speech) are becoming impossible to explain away. All we need in the House is a majority to impeach. A couple actual Republican patriots (if any exist) are enough to do it.

Don't concentrate on a conviction! The Senate gets immense powers to access Trump's medical records if it's an impeachment trial.

All we need are the MRIs of his brain.

You get it. It could even end up like Nixon: Trump resigning rather than face the public seeing the prune inside his head.