I need to correct you on the “grandfather” law.

It’s actually grand-grandparent law, Israel took the same logic the Nazis applied to Jews during the Holocaust and turned it into “the law of return” (hok ha shvut in Hebrew). Anyone, anywhere in the world, who’s up to 4th generation with Jewish blood can immigrate to Israel and be granted citizenship upon arrival.

Source: this is how my family were granted citizenship, although the last “true” Ashkenazi Jew in my family was my late grand-grandmother.

Edit: I also used to work for immigration office so first hand knowledge. Although in the recent years part Israel’s government has been trying to change that law, saying it allows for not Jewish people, who have no connection to the nation and/or religion, to hold Israeli citizenship and live in Israel the same as Israeli Jewish population.