There's already a brain drain going in the US Government, as they replace experienced leaders and workers with blind loyalists.
The silver lining is that they have given their opposition the gift of competence. By firing all their competent, knowledgable people, they have driven them straight into the enemy camp.
It gets SEEN. Sociopathic Oligarchs generally live far away from every one else, so you are a tree screaming in an empty forest - nobody hears it.
Instead, fill the streets in front of their offices, so neither they, nor (more importantly) their employees can get to work. It will piss off the other tenants in the building, the building owner, the buildings and businesses next door and across the street, etc. The message gets sent that it's this Sociopathic Oligarch's behavior that is causing all this trouble, and they'll want him gone, too.
Make their lives miserable.