In 1970, the right of entry and settlement was extended to people with at least one Jewish grandparent and a person who is married to a Jew, whether or not they are considered Jewish under Orthodox interpretations of Jewish law.

- https://en.m.wikipedia.org/wiki/Law_of_Return

Practicing Judaism as a religion is basically irrelevant to whether one is legally considered a Jew in Israel. I mean hell, 20% of Israeli Jews don’t believe in a deity yet get all the perks one gets due to being a Jewish citizen of Israel. See: https://en.m.wikipedia.org/wiki/Irreligion_in_Israel