04/06/2008 at 02:00 PM EDT
David Cook quickly bounced back from his brief hospitalization
due to high blood pressure and heart palpitations, but the American Idol
finalist is coping with more than the weekly eliminations.
His older brother Adam Cook is battling cancer, sources confirm. David hasn't spoken about it, the sources add, out of respect for his brother – and because he didn't want to seek sympathy votes. But he has performed with an electric guitar emblazoned with his brother's initials "A.C."
Cook is not the first idol to compete while dealing with a personal crisis.
"The week before we came up for the Top 24, my best friend passed away, and I was just like, 'I don't know if I can go out there,'" last year's champ Jordin Sparks tells PEOPLE. "I went to the funeral and came back and then my uncle passed away – and then my grandma ... and so I had three deaths go on during the show."
The blows tested Sparks physically as well as mentally, she said last week at a Hollywood PSA shoot for DoSomething.org and Staples School Supply Drive To Do Something for students who can't afford school supplies.
"It's hard because you have to go out there and put this smile on your face," says the singer. "It's very exhausting, and it's very overwhelming and kind of gets to you. I mean I got sick a couple times, just because I was so tired and kept trying to do all this stuff and it was crazy."
Still, if personal matters were to become very serious, it's possible that Cook would be allowed time off from the competition to be with his family.
"It's only ever happened once and that was in the U.K.," Idol
producer Nigel Lythgoe told reporters in a conference call. "We gave them a week out."
Reporting by JED DREBEN, MONICA RIZZO and PAM GROUTLike this story? Click on the Yahoo Buzz! button below to Buzz it up!