04/15/2008 at 12:00 AM EDT
In a heart-wrenching American Idol
performance, David Cook
sang "Always Be My Baby" on Tuesday night while his brother Adam Cook
, who is battling brain cancer, watched from the front row.
When David finished the Mariah Carey
song, Adam gave him a standing ovation and David wiped his eyes.
"You have tears," host Ryan Seacrest
said after giving the audience the number to vote. "He's in tears right now."
David could only answer, "Yeah."
During a commercial break, David walked down to hug his brother in his seat. All three judges -- Simon Cowell
, Paula Abdul
and Randy Jackson
-- also hugged Adam.
Adam, 36, who traveled to Los Angeles from his home state of Indiana, arrived at the studio 40 minutes before the live telecast began and took a seat right next to Desperate Housewives
star Teri Hatcher
and her daughter.
Two weeks ago David had a difficult time concentrating
on the show because he had learned his brother's condition had worsened. Despite his fragile state, Adam's doctors allowed him to travel
to the Idol
show accompanied by a medic and a nurse.
"His brother came to town a few days ago, and he's not in the best of shape and you can tell it's affecting David and everything," says dancer Lacey Schwimmer
, of So You Think You Can Dance
, who has stepped out with David
recently. "But I think it's a good thing that he's here because it shows that his brother is still supporting him."
Schwimmer adds: "He's just really happy his brother is here."
Adam is expected to attend Wednesday night's Idol
results show before returning to Indiana on Thursday. --Jed Dreben and Monica Rizzo