Earlier in the night the father had seriously assaulted his wife, punching her several times to the face and kicking her.
Attempting to seek refuge, she took one of her young children and fled to her son's home. The father followed.
He banged on the doors and abused the family from outside the home, with doors locked and curtains drawn.
The police were called but before they arrived the son attempted to confront his father.
A violent minute later the father was found lying on the deck, stabbed six times, and bleeding.
"That's why I grabbed the knife, because if I go out there [with nothing] he's going to give me a big hiding," the accused explained in his police interview.
"Seeing my mum, I knew what he was going to do to me he would do to her, that's why I grabbed the knife."
Kayes asked the jury today: "Was what he did in defence of himself or another?
"Are you sure that the force that he used was not reasonable?"
Wallwork reread parts of the defendant's statement to police in an attempt to show his state of mind after the stabbing.