In simple terms, both Boris and Farage have realised that Brexit, which they both claimed to support, will, most likely, be an unmitigated disaster, not least because none of the Brexiters had the faintest clue how Brexit would be managed. The awful truth has now dawned of both these individuals and they share a common desire not to have to consume the shit-sandwich that will be Brexit. In fact, although there is meant to be a Tory Leadership election, the Brexiteers will be very happy if, at least in the short term and maybe in the longer term as well, if Teresa May gets the job. That will give them the perfect excuse to blame the Remainers when Brexit doesn't happen.
So, whilst all of this sad manoeuvring is going on, Dave (He of the Big Tent) will be sunning himself in the highly paid shelter of directorships which usually follow senior politicians who exit the political field. Don't be surprised if Dave indulges in some sniping of his own.