Can someone be retroactively Jewish if their mother converts?

Probably a dumb question, but what the heck? :)

I heard this story on NPR today. In Israel, When Is A Jew Not Jewish Enough?

The story is about a man who went to Israel to fight in their army, but was told he wasn’t “Jewish enough” because his mother wasn’t born Jewish, she converted. However, the article also states, “The army offers its own three-month conversion course for those serving. Those who pass will be considered Jewish by the Israeli government, with the right to get married and be buried in Israel.”

If Mr. Leavitt’s mother, for some reason, went through the Army’s crash conversion course, could he be retroactively considered “more Jewish” since his mom would then be acceptable? Or does she have to be a “real” Jew at the time he’s actually born?