Hayley described Patrick as having a face that was “blood, blood, blood red.”
“There was like froth coming out of his mouth, he was screaming,” she added.
On hearing of Peter’s death, Owen told jurors he knew he had to “go back and face the consequences”.
He handed himself in to a police station with his mother the next morning.
Owen, of Hill Rise, Darenth, also admitted to inflicting grievous bodily harm on his cousin’s partner, Mahon.
Patrick was found guilty of inflicting GBH on Mahon on Thursday.