> who will do it?

Preferably one of his own, but they're more likely to be waiting for the Grim Squeaker to save them the trouble and the paperwork.

Once the offender goes (naturally or otherwise), I foresee an almighty cat-fight; but all we may see of that will be an announcement that he's having medical treatment, and that a committee of three or so is doing a holding exercise. The "treatment" will be embalming, and the triumvirate will rule in his name till they've settled their truel.*

* Approximate paraphrase, as Heinlein's Friday is too thick to riffle through in a hurry.