(CNN) -- Bret Michaels' "sheer will to live" kept him alive long enough last week to allow doctors to stabilize his condition after he suffered a massive brain hemorrhage, his neurosurgeon said Friday.
The rock singer and reality TV star was in critical condition in the intensive care unit at Barrow Neurological Institute in Phoenix, Arizona, a week after he suffered the rupture.
His sister Michael Sychak told HLN's "Issues with Jane Velez-Mitchell" that Michaels was watching television at his home near Phoenix when he was stricken by an excruciating headache on the evening of April 22.
"Bret's fight to stay conscious during the hemorrhage and get to the emergency room" was key to saving his life that night, said Dr. Joseph Zabramski, the head of the medical team treating Michaels.
"He has an unbelievable fight in him and told me what kept him alive at the moment of the hemorrhage was that he 'did not want his family to wake up and see him lying unconscious in the middle of the floor,' " Zabramski said.
His recovery is complicated by "a few roadblocks," he said.
Michaels has hyponatremia, a lack of sodium in the body, which leads to seizures. He also suffers severe cranial and back pain from blood drainage, he said.
An emergency appendectomy 11 days before the rupture, and his lifelong history of Type 1 diabetes are also factors slowing the recovery, he said.
"Bret's sheer will to live and fully recover is undeniable," the doctor said.
Zabramski and his team will talk more about Michaels' illness and recovery at a news conference at the hospital on Tuesday.
Michaels is able to talk, his sister said.
"He sounded good -- as good as you can when your brain's throbbing," she said.
A statement published on Michaels' official website earlier in the week said his band might resume its concert tour as soon as May 26 "provided there are no further complications."
Michaels, 47, was the lead singer for the '80s glam-metal "hair band" Poison. He became a reality star on the VH1 show "Rock of Love with Bret Michaels." He has also appeared on "Celebrity Apprentice."