"He was obviously reasonably stressed after the home invasion incident, so I ring him everyday and see him everyday.
"On Friday I rang him about 7 o'clock at night...and he was a bit breathless and a bit stressed."
Mr Morrissey went to his father's home about 15 minutes later and discovered him dead on the kitchen floor.
"It must have been pretty instantaneous."
The family had noticed his health had deteriorated since the attack, but Mr Morrissey said it was not known whether it was the cause of his father's death.
"But I'm sure the incident caused stress, which caused other things - it might have been a catalyst."
A post-mortem examination would be held tomorrow into the cause of Jack Morrissey's death.
On the night of the attack, he had answered the door to two people who knocked him to the ground with a broom handle.
He hit a coffee table, cutting his arm and knee. He activated his St John medical alarm as he lay on his lounge floor.
Paul Morrissey described his father as a generous and kind man who always had time for his family.
"He retired early from the police force at 55 and that was just in time for all his grandchildren. He spent many hours taking them swimming and was a very generous man."
Jack Morrissey's funeral will be held on Thursday.
