When he entered the bedroom where the attack had happened, he saw a silhouetted figure standing in the room, who then turned towards him and repeatedly struck him over the head with a hammer.
The two boys were discovered in their beds a few minutes later and had suffered skull fractures and injuries to their ribs, spleen, a punctured lung and internal bleeding.
The court heard both were living with the “long-term consequences” of the attack but have no memory of it. One boy suffered permanent brain damage, the court heard.
Mr Roffe-Silvester, who received six blows to his head, made a full recovery.