TEPCO says "His life is not in danger."
Judging from the past 16 months of communication by TEPCO and the Japanese government (who are one and the same at this point, after the effective takeover of TEPCO by the government), it may simply mean "not in immediate danger", and by "immediate" it means "instantaneously".
TEPCO announced the news 4 days after it happened.
From Jiji Tsushin (7/30/2012):
Former Fukushima I Nuke Plant Manager Yoshida underwent emergency operation for cerebral hemorrhage, his life is not in danger, says TEPCO
TEPCO announced on July 30 that Masao Yoshida (age 57), former plant manager of Fukushima I Nuclear Power plant, complained of feeling ill on the evening of July 26 when he was away from home, and that he underwent an emergency operation for cerebral hemorrhage at the hospital he was brought to. The operation was successful, and he is conscious even though he is still in grave condition. TEPCO says his life is not in danger.
Since the start of the nuclear accident on March 11 last year, Mr. Yoshida led his team of workers to deal with the accident as the plant manager. He was diagnosed with esophagus cancer and hospitalized in November last year. He resigned as the plant manager at the end of November and has been receiving medical treatment at home.
TEPCO's Junichi Matsumoto didn't explain the details of when Yoshida suffered cerebral hemorrhage, saying it was his family's wish. According to the doctor [at the hospital?] there is no direct relationship between the cerebral hemorrhage and the esophagus cancer.
TEPCO announced in December last year that Mr. Yoshida's radiation exposure level after the start of the nuclear accident was about 70 millisieverts. The latent period for esophagus cancer is between 5 to 10 years. At the time of the announcement, TEPCO quoted Dr. Makoto Akashi, Executive Director at National Institute of Radiological Sciences, who said the possibility was extremely low that [Yoshida's esophagus cancer] was caused by radiation exposure.