Schumer will let those 5 vote yes, and a couple of the others. He just needs 40 votes to win a filibuster.
. . . and that is why it is critical that good candidates be recruited for at least the dozen most vulnerable (in 2018) Democrat senators.There won’t be an incumbent Democrat (or anyone, period) running for POTUS in ’18 as there was in ’12. Those 25 Democrat Senators know what happened to many of the members of their caucus when they faced that circumstance in ’10 and ’14.
Likewise the Republicans know that they will face uphill circumstances themselves - tho not as extreme as what the Dems will face in ’18 - in ’20 and ’22. They know that if they hope to control the Senate after ’20 they had better pick up seats in ’18. So it’s logical that the Republicans would work hard to put Senate Democrats on the wrong foot in the next Congress. And for all 25 of those Democrats needing reelection to be wary of unforced errors like opposing SCOTUS nominees favored by a majority of the voters in their home states.