He's got as far as he has (which admittedly isn't very) by ignoring the "gentlemen's agreements" that are the basis of our "constitution" but aren't actually enforceable if someone chooses to go against them. Things like not threatening to game the date of an election to get what he wants, not proroguing Parliament for an unreasonable period, providing a teller for an amendment. Along with some fairly dispicable actions as Mayor of London (several tens of millions of public money wasted on the Garden Bridge) and the lies of the Leave campaign, it's clear he has no shame or conscience. We should have no expectation that he will do the "right thing", unless it also happens to be in his personal interest.
In a rational world an incoming government ought to have three priorities:
- A referendum on Brexit
- Electoral reform to make Westminster somewhere near proportional
- Codifying the constitution so it is absolutely clear what governments can and can't do
I'm not confident we'll be back to a rational world any time soon.