If you stretch the meaning of “unconstitutional” past the point of all usefulness, sure.
I should like this argument more than I actually do. It’s originalist at root, and the guy has damning quotes from Hamilton and Madison about the evils of super-majorities. In terms of reforming or ending the filibuster, he makes a solid case.
In terms of having the Supremes declare it “unconstitutional,” he’s much weaker, because arguing that anyone’s “rights” are being violated by the filibuster is going to be a tougher sell. It relies upon the wearisome mission-creep of the “one man, one vote” rule.
The Senate created this mess. The Senate should fix it.