Craig Wilson had previously served a two year sentence for assaulting his wife and his son Benjamin said launched his attack to defend his mother.
A son who battered his abusive father with a hammer in a bid to stop him from attacking his mother has been jailed for six years.
Benjamin Wilson grabbed the heavy weapon and raced upstairs at the family home after hearing crashing, shouting and commotion coming from the bedroom.
Wilson, 22, then went into the room and beat his 46-year-old dad Craig with the weapon after claiming he was defending his mother.