Did you find out once he died? That is how I found out. Even though I never lived close to my Aunt and Uncle, I was very close to them in a loving way. Never did I hear anyone speak about him being a Mason until then. The Lodge sent his widow a Bible and their condolences. Before my Aunt died, I asked if I may have his books, for I wanted to read for myself what I had been hearing about to see if it was true.
Both my Aunt and Uncle became aware of the underlying unchristian ideas through some other christians they where friends with. My uncle started reading christian anti-freemasonry books on the subject and his eyes were opened and he then did repent. However, I have a feeling he never received the peace deep down that he was truly saved, for he asked me questions about salvation at one point that only a person who doubted it was possible to be saved would have asked. If I had only known that he was a Mason at that time, I would have understood where he was coming from in his fear.
After he died and then my Aunt, I went through all his masonic things that he owned and realized that the next step up in his freemasonry was becoming a "Worshipful Master"...I hate to think what that would involve. He however, never advanced to that spot and dropped out of freemasonry, claiming poor health.
Despite it all, I believe that my uncle was saved by the blood of Jesus. Who knows, perhaps "Worshipful Master" may have been where he would have lost his salvation forever if he would have continued. Thank you Jesus for saving my uncle before he died and thank you for the christians that were strong in their faith to share with him the truly Good News of Christ and His forgiveness. Amen