Ron Legg, 50, who had the mental age of a child, spent days living with the bodies of his parents - Charlie, 83, and Vera, 79 - unable to tell anyone what had happened. The bodies were discovered yesterday at the family's country cottage in Winterborne Stickland, near Blandford, Dorset.
Mr Legg, a retired dairyman and his wife, were both almost blind, but they insisted on continuing to care for both themselves and their son. The couple also had two other children, a girl and a boy, but both had died as infants.
Mrs Legg's sister, Kathleen Staunton, 73, said: "Vera and Charlie loved Ron so much they could not let him go. They adored him, but just lately they were having trouble looking after even themselves and it was all getting too much ... I feel so sorry for Ron. It seems he was in the house all the time after they died, but he would not have known what was happening or what to do about it."
Mrs Legg's brother-in-law Ken Gillies, 67, said: "They were just too proud to accept that they could no longer fend for themselves."