He went to court 5 years ago and proved he was legally sane.
As he is legally sane he cant be sectioned. The judge basically agreed that he did want and planned to stab his mother to death and rape her however criminal thoughts or action are not proof of insanity nor a reason for him to be sectioned.
He may have / could have a personality disorder rather than a mental health type disorder which can be managed medically
The judge took care in looking at all the evidence and accepted that he had the legal capacity and ability to form criminal intent.
She recomended that the Gardai investigate the witness statements which led to the prison term.
The High Court case pdf and link was posted on MN at the time