When facing death, one can convert very easily. Death, in reality, changes one’s perspective. Jewish is not a disease, it’s a belief.. and a few weeks to live, gives one time to rethink and be sure... very sure.
He was a brilliant man and very ethical in the true Judeo-Christian way, which the modern world has nearly abandoned (if not to say destroyed).
God knows all and God will know what was in his heart. I never felt he was a rebellious “Jewish atheist,” ala Marx or Freud, but perhaps just an intelligent man who couldn’t find a Jewish place to be between the Hasidim and the famous Upper West Side “Democrat Temple Go With The Flow.”
I didn’t always agree with him but I always respected his opinion because he was morally sound and honest. As Christians say, following St. Paul, he ran the good race.
This Catholic will be praying for him in his last weeks.