A year ago Mr. Sharon, who is 83, was transferred from a hospital outside Tel Aviv to the family ranch in southern Israel. But Gilad Sharon said that the stay was brief and that his father was returned to the hospital, where he had remained. He hopes that in the coming year his father will come home permanently.

“The problem is Israeli bureaucracy,” Mr. Sharon said. “I think it would be better for him to be at home.” He added that his father had been visited every day since his stroke by him, his wife, Inbal, or his brother Omri. “We haven’t missed a single day,” he added.

He said that in recent times there had been no improvement in his father’s condition.

The book asserts that doctors and nurses urged the family to let Mr. Sharon die after his stroke in January 2006 because, as it paraphrases one doctor as saying, “Based on the CT scan, the game was over.” The Sharon brothers would not hear of it and insisted on an operation and other efforts to keep their father alive.

“I told them about a dream I had had many years ago,” Mr. Sharon recounts in the book, speaking of his discussions with the medical staff of Hadassah University Hospital in Jerusalem. “In that dream I was with my father in the hospital. He was lying in bed, surrounded by medical staff, and they had all either given up or lost hope and were about to leave, and my father didn’t say a thing, but he stared at me with this look, with those green-gray eyes of his, and I knew I would never give up, and that I simply would not leave him. This was a dream I had when my father was healthy and strong and the scenario was completely divorced from reality. I did not tell a soul about the dream at the time, but now I shared it with them and my fear that it was happening now and that I would never be able to forgive myself if we did not fight to the end.”

Image Gilad Sharon, Ariel's son. Credit... Ziv Koren.

While it has long been assumed in Israel that Mr. Sharon was kept alive due to his sons’ insistence, the book offers the first public acknowledgment and detail of the decision. Mr. Sharon was widowed twice, and his sons are in charge of his farm and his care.