Like most things about Orson Welles, the truth seems to be based on who is telling the story.
Most of the obituaries at the time, said Welles' died in his sleep, alone, during the middle of the night, and was found the next morning by his driver (One wonders, where was Oja Kodar?). But according to Gary Graver, Welles was working on material for a version of JULIUS CAESAR.
Gary Graver's full comments are as follows:
Graver: The odd thing was, when Orson died in the middle of the night, the next morning we were supposed to shoot on a stage at UCLA. Orson was going to do a version of JULIUS CAESAR, playing every part himself, so he wasn't in bad heath, he just had a heart attack. It was bizarre, because Paul Stewart, who played the butler, Raymond in CITIZEN KANE, was the first person to go into Orson's house and find him dead. In CITIZEN KANE Paul was the character who heard Kane's famous last words, "Rosebud". Well, Paul was at the Director's Guild, which was close to Orson's house, so he was going to pick-up Orson and bring him down to UCLA on the morning that he died.
Orson was cremated and Orson's daughter spread some of his ashes in the mountains outside of Seville, in Spain, and some were buried in an old well (in Ronda, Malaga, Spain) owned by Antonio Ordonez, a bullfighter, who was a friend of Orson's. It's also where Orson had lived when he first visited Morocco and Spain in the summer of 1933.