Grieving family and friends could only look on as paramedics battled to save Tam Gourlay, 62.
The father-of-three was taken to Forth Valley Royal Hospital but was later pronounced dead.
Mr Gourlay, of Stenhousemuir, Stirlingshire, had been at Falkirk Crematorium for the funeral of his son Gregg, 43, who suffered an aortic aneurism and died in Forth Valley Royal Hospital, Larbert a week earlier.
Gregg's widow Maureen, 42, said the double tragedy had been horrendous for the entire family.
Along with children Jenna, 15, and Dean, 11, she had just entered the crematorium when the incident occurred.
She said: "He was right in front of us when he collapsed.
"A lot of people tried to help him and others called for an ambulance, but sadly he didn't make it."
The service eventually went ahead, but later shocked mourners heard of the second tragic death.
Mr Gourlay senior's funeral was held at the crematorium on Hogmanay.
The devastated family faced a heartbreaking festive period after the sudden loss of a devoted father and a much-loved grandfather.