The Scottish Public Services Ombudsman ordered paramedics to apologise for not properly immobilising the man on a stretcher after the fall at his home two years ago.
A report on the incident, which refers to the couple as Mr and Mrs C, explains that the man fell after being out with friends for drinks.
His wife and son moved him to the living room and called for help, saying he had been unconscious.
The crew seemed reluctant to take him to hospital and made comments about "drunks", she alleged.
The man was then moved by wheelchair to the ambulance and was later found to be unable to move his legs.
The ombudsman upheld the complaint about the Scottish Ambulance Service.
"I, therefore, recommend that the service make a formal apology to Mr and Mrs C for their failure to properly immobilise Mr C after the incident on 24 March 2012. Also, that they apologise for the inadequacies of their internal investigation," the report concludes.
"Finally, the service should externally audit their complaints handling processes to ensure that they are sufficiently robust and fit for purpose."
The service has accepted the recommendations and will act on them accordingly, the ombudsman's report states.