My coworker admitted to me that he was a Klan member

He started the conversation by saying “To be honest, if we had known each other a few years ago, I would’ve killed you.” For context I am a white trans man. I didn’t react, & instead asked him questions so he let his guard down & told me all about how he was in the Imperial Klans of America & how much of a bigot he “was”. He admitted all of the following in confidence to me: He has beaten a black man, read Mein Kampf, listened to every speech from SS leaders, still currently uses his email address that ends in 336 (SS reference), has been on national news for racist house decorations that he refused to take down, and he wanted to “legally kill people” in war…and did. We spoke for hours. He claims that he’s changed & a man of god now. I asked him a million questions about his past, & he asked me questions about me living as a queer trans man. It was an entirely respectful conversation, & by the end of it he hugged me. I have been thinking about it all non stop since the discussion. I knew racists exist because I see them everyday on the internet, & I knew people hide their bigotry on the outside mostly, but to know someone who was once so married to their racism & hatred makes me sick to my stomach. & of course I’m sure that hatred didn’t really fully go away like he might say. I haven’t told anyone at work about this.