You do understand that Jews are an ethnicity as well as a religion. He was an ethnic Jew who grew up in a religiously Jewish household who also practiced Judaism himself in the form of which it was in that time. You can say that he broke away from Judaism, which would be true, but he was still ethnically a Jew through his mother. Also the idea of modern Judaism didn’t exist 2000 years ago. So no, there is in no way, shape or form in which he would have practiced it at any point in his life.