We are stuck with him. We’ll never get him out of the Senate. He is an immature jerk, undeserving of respect or stature. He will side with McCain and Graham, and the Dems as often as he can.
Trump is the head of the RNC and the party. Her can and will control the resources used to help a candidate get elected or re elected. Trump also can put pressure on the McConnell to ice Rubio and keep him off of certain committees of high visibility and which help candidates in their bid for re election.
The president of the United States is a VERY powerful position and the power he wields within the Party is enormous, especially when he has the backing of the constituency as Trump clearly does.