O'Neill's family alleges that toward the end of his life, he began having mystical experiences, which they claim influenced much of his writing, including his songwriting, journals, and his play, They Walk Among Us, which features a character that O'Neill seemed to have based on himself.
O'Neill was at the Station nightclub for the concert by the band Great White on February 20, 2003 with his bandmate from Shryne, Jon Brennan, and another friend, Albert Dibonaventura.