Well, obviously they need to treat them as equals. That is almost certain to create fireworks, but they already have fireworks (and blown tires) with how they were dealing with it. In the end, I suspect they will be forced to say goodbye to Vettel after 2020 for the sake of team peace. It is clear that he cannot team with a competitive teammate. He needs to find a team where he is clear #1 (McLaren?).