Paul may be an asshole but he’s not stupid. He is smart enough to know that this is Trump’s party now and crossing over a hissy fit can bring problems.
Trump going for a Bushie is a sign of consolidating power, and also extending an olive branch to the Bush wing of the party. Just not the Jeb Bush wing.
Trump is going to need allies, as all the people who brought him to the dance are gone.
The risk is that Bushies fill the (whole lot of) empty slots around the administration.
Who will co-opt whom first?