Why Did Luke Woodham's mother Mary Ann Woodham blame him for her divorce and was she ever nice to him before?

Luke Woodham for those who don't know was a teenage boy who caused a school shooting in Pearl High School in October 1st 1997 after he got bullied for his weight and being a nerd, his parents got divorced in 1992 when he was 11 years old and his mother blamed him for the split up, do u think it was wrong of his mother and fellow students treating him like that?