Judge James Goss QC said he was minded to make Daniel Taylor, 21, subject to a hospital order for the manslaughter of Jack Taylor.
But the judge said he needed to hear further submissions before making a final decision.
Jack Taylor was stabbed at a house in Rookes Avenue, Bradford, in February.
He was taken to Bradford Royal Infirmary where he was pronounced dead after suffering multiple stab wounds.
Jack's sister Rachel was also injured in the incident.
Daniel Taylor pleaded guilty to the manslaughter of Jack earlier this year and today admitted wounding Rachel.
These pleas have now been accepted by the prosecution.
The court heard Taylor was a paranoid schizophrenic and he was probably suffering an abnormality of mind when he carried out the attacks.
Taylor, of Richardson Avenue, Bradford, was due to be sentenced by Judge Goss today at Bradford Crown Court.
But the judge adjourned the case until December 15 at Leeds Crown Court.
Taylor was remanded into the custody of Rampton Special Hospital.