No, Shlomo Sand cannot be Jewish.
By his own definition in his recent book, the Jewish people is an "invention" which a person cannot be part of, an imaginary entity which has no claims to any particular peoplehood and an invented fantasy with no legitimate reason to have established the Jewish State of Israel.
Ironic that Sand is by all of the definitions which he rejects, definitely a Jew and quite an enigmatic part of the Jewish people.
Sand teaches at an imagined Jewish university which presumably pays him in make-believe shekels and lives in that fictional Jewish state and speaks a concocted Jewish language.
The Hebrew version of his unfortunate book (In English: "The Invention of the Jewish People") was a best seller in the Israel which he derides.
The Times has an appropriately quizzical account of the book and its author.
We never know what to make of one of our self-hating brethren who relishes his notorious obnoxiousness for no purpose other than his own self aggrandizement. We make note of the sad cultural fact and move on.