I'm afraid the answer to your question certainly does not end very well for Boy (as is evidenced by his suicide and despair); however, it is true that Ramsay shows Boy "the error of his ways."
First let's discuss what "the error" of Boy originally was. In his youth, Boy throws a snowball that hits Mrs. Mary Dempster. She is the pregnant wife of the minister of the local Baptist church. Boy throws the snowball (which was really a snow-covered rock) that sends Mrs. Mary Dempster into premature labor, and she has her little Paul Dempster almost three months early! This causes all sorts of problems for the family (ending with Mrs. Dempster's insanity and Paul's joining a circus as a magician). At that point, Ramsay blames himself. Why? Ramsay dodged the snowball which was meant for HIM.
A boy is a man in miniature, and though he may sometimes exhibit notable virtue, as well as characteristics that seem to be charming because they are childlike, he is also a schemer, self-seeker, traitor, Judas, crook, and villain - in short, a man.
Later in life, Ramsay decides to convince Boy of what you deem as "the error of his ways." He does this by actually introducing Boy to Paul Dempster (now a famous magician). This convinces Boy that it was his snow-covered rock that made Mrs. Dempster go crazy and Paul Dempster eventually join a circus as a magician and hypnotist. After Boy and Paul are introduced, Boy is found dead. How? He is underwater in his car, a stone lodged in his mouth. It is implied that Paul is the one that convinced Boy of his culpability and encouraged him (through hypnosis) to kill himself.