Trump won't let Healthcare die until he kills it first.
Yesterday (Sunday), Trump's stance on changing Obamacare to Trumpcare went from "Let it implode" to "I'll destroy it myself" to "Kill the filibuster and pass the damned Bill."
I believe that Trump believes he has to have the last word on this for a couple of reasons. One, if he doesn't John McCain has the last laugh and word. Don't forget that Trump zinged McCain during the campaign where Trump famously stated that McCain wasn't a hero because he got captured in North Vietnam. With his vote, McCain bested Trump. And Trump can't stand that. Two, in his Tweet, when Trump excoriates Senate republicans that their inability to pass healthcare "reform" means that they're being laughed at. In true Freudian projection, Trump is talking about himself. And for once, it isn't his imagination: he IS being laughed at for being such a buffoon. He wants to decimate Obamacare just so he can say he "won". He wants the last word, even if it means destroying the White House, the Republican Party, American democracy, etc.
In other words, to Trump, it isn't enough to allow Obamacare to "die on the vine". He has to help in order to have the privilege of saying "I told you so."