John Robinson was attacked on Wednesday as he returned from watching the Brazil-Scotland World Cup match with his son, Jonathan, at a social club in Birmingham. He had been celebrating his 68th birthday.
Father and son got into an argument with about seven teenagers who were kicking a fence about 100yds from their home in Yardley Wood.
Jonathan, 30, is believed to have chased several of the youths after one threw a brick at him. When he returned a fight broke out, during which his father was severely injured.
A shopkeeper - who was too frightened to be named - said he saw a number of youths lashing out with their fists. "I was looking out of the shop window and heard shouting from an alleyway nearby. Then I saw youths surround one of the two men and start jumping on him and punching him. They were like a pack of animals."
After the fight he ran across and found Mr Robinson lying in a pool of blood. "He was in a really bad state and was having bad trouble in breathing."
Another neighbour said: "I ran down with some blankets and saw Mr Robinson lying there in a pool of blood. His son was kneeling at his side holding his father and crying. He was just too upset to talk."
Mr Robinson's family were at his bedside in hospital yesterday where he was described as critical with serious head injuries.
Detective Superintendent Bill Guest, of West Midlands Police, described the attack as "despicable", and said Mr Robinson was "public spirited and courageous".
As Mr Robinson lay bleeding on the floor a passer-by laid a T-shirt under his head for a pillow. Police are appealing for him to come forward.
Det Supt Guest said: "This is a tragic incident. What started off as a pleasant day out, a birthday celebration ... turned into a man fighting for his life. This is a despicable incident."
One distraught neighbour said Mr Robinson, who lives with his wife Doreen and sons Jonathan and Simon, was a quiet family man who enjoyed walking and fishing at the weekend.
Neighbour Elsie Billings, 77, said the previously quiet neighbourhood had been plagued by a gang who abused people and vandalised property.Reuse content