Question about Immortal Alfred Cahill

In the episode "Avenging Angel," while they never said exactly what was wrong with Cahill, (just that he was insane), anyone else get the impression that he was a paranoid schephrenic, with delusion of grandeaur? I really think he was. They talked about him having hallucinations, and he would put his finger to the side of his head, the way schephrenics do when they are hearing voices. He also said he was abused by his stepfather, who knew he was different the minute he saw him. I wonder if he was hearing voices, and his stepfather thought he could beat it out of him? Even though his behavior was rather disgusting, I felt sorry for him, because if he was mentally ill, he couldn't help it. I think Duncan felt sorry for him, and wanted to help him, but sadly, he was to messed up, and you can't talk schephrenics out of their hallucinations. He wasn't evil, he was sick. My guess is in death was the only way he could find peace.