Actually Leopold Frankenberger, a Jewish Austrian, was rumored to be Hitler’s grandfather for decades. A DNA study was done years ago on Hitler’s remaining relatives that did establish haplotype E1b1b presence, which is North African/Berber and present in both Ashkenazi/Sephardic Jewish populations.
Lavrov is merely repeating these well known claims. It used to be brought up routinely to show the hipocrisy of Hitler’s prejudices.
It doesn’t matter. Since Hitler himself didn’t consider himself to be “Jewish” the slightest.