Two of Sir Alex Ferguson's grandchildren and their mother were hurt in a head-on car crash just hours before his Manchester United side beat Arsenal 3-1 in their Champions League semi-final.
Darren Ferguson says his 10-year-old son Charlie was in a hospital intensive care unit after undergoing a successful operation.
He added that his six-year-old daughter Grace was fine while their mother Nadine was still in hospital recovering from her injuries.
Darren Ferguson, who is manager of League One or third division side Peterborough United, is estranged from his wife.
Newspapers reported Ferguson had considered returning from London where the semi-final was being played to be with his injured relatives, but decided to stay to oversee the game after being told their lives were not in danger.