Ambulance bosses are looking into why an 80-year-old man had to wait almost 24 hours for an ambulance days before he died.
John Williams fell and hit his head at home in Gowerton, Swansea, last Tuesday, but was not admitted to hospital until Wednesday.
He then died on Sunday morning - five days after being taken to Morriston Hospital in Swansea.
The Welsh Ambulance Service said a full investigation would be carried out.
Mr Williams's son Darren, 48, said the ambulance was called shortly after 08:30 BST on Tuesday and the family had been expecting a response "within 40 minutes to an hour".
Despite ringing 999 three further times on Tuesday, the ambulance did not arrive until 07:30 on Wednesday.
Mr Williams then had to wait seven more hours outside Morriston Hospital before he could be admitted.
Heart 'gave up'
His sons said they were advised not to move him while waiting for an ambulance and their father did not have any medication, including some for his heart, for 36 hours.
After his father died, Mr Williams said he was told his heart "gave up".
"I can't help thinking that all this has contributed to my father's passing," said Mr Williams.
He said the ambulance crew, when they arrived, were "brilliant" and "just trying to do their job in a very difficult situation".
A spokeswoman for Abertawe Bro Morgannwg University Health Board said Mr Williams's condition began to deteriorate after he was admitted to hospital.
Claire Bevan, director of quality, safety and patient experience for the Welsh Ambulance Service, said: "We would like to extend our sincere condolences to Mr Williams' family at this very sad and difficult time.
"We want to ensure a full investigation is carried out into the wait that Mr Williams experienced and we will be communicating with Mr Williams' family."