The 41-year-old suffered a serious head injury during the attack in Kilwinning, Ayrshire, by five or six young people.
Earlier his 21-year-old stepson, who has health problems, was verbally abused and attacked by the gang.
The man was followed from Main Street and assaulted between midnight and 1am yesterday.
He ran to his home in the town's Woodwynd area where his step-father went out to help him and was attacked.
Detective Sergeant Ian Ross said: "This was a terrifying experience for the young man and his stepfather, who sustained a nasty head wound, after the young man was followed home by his assailants.
"We are continuing extensive inquiries into identifying the youths responsible."