HONOLULU -- Sen. Barack Obama arrived Thursday evening to spend time with his gravely ill grandmother, Honolulu resident Madelyn Dunham.

Obama's campaign jet arrived at about 7:15 p.m.

A motorcade took the Hawaii-born Democratic presidential candidate to Dunham's Beretania Street home. He spent an hour there before heading to a Waikiki hotel to spend the evening.

Obama is scheduled to spend Friday with Dunham before leaving in the evening for the mainland. He is scheduled to appear in Reno, Nev. on Saturday.

"She's gravely ill. We weren't sure and I'm still not sure she'll make it to Election Day. We're all praying and we hope she does," Obama told ABC's "Good Morning America" before he left for the islands.

The senator does not have any campaign events scheduled for Hawaii.

Political historians said it is the first time ever a presidential candidate has left the campaign trail so close to Election Day.

Obama's 85-year-old grandmother is suffering from cancer and recovering from a broken hip, a source told KITV. She celebrates her 86th birthday Sunday.

For Obama to leave a presidential campaign just two weeks before an election is unheard of.

Friends said Obama's urgency to get here could be fueled by one of his greatest regrets. That is not being in Hawaii for the death of his mother, Ann Dunham, who died at age 52 of ovarian cancer.

He said he did not want to make the same mistake twice.

"One of the things I wanted to have a chance to sit down with her and talk to her. She's still alert and she still has all the faculties and I wanted to make sure that I don't miss that opportunity right now," Obama told "GMA."

Obama's senior adviser Robert Gibbs said Obama's grandmother is tremendously important to him. Dunham and her husband, Stanley, raised Obama in a Beretania Street apartment.