, earlier this month was filled with tears for the "American Idol" winner.
Speaking of his brother throughout the Friday concert in front of 450 in Akron, Ohio, he struggled through some songs – even walking out in the middle of one of them.
He left the stage abruptly while singing "Come Back to Me," and his band followed him. As the crowd chanted for him to return, he stood in a hallway with his hand to his face.
When he returned five minutes later, he told the crowd: "It's been a hell of a week. It's good to be here tonight."
The crowd was well aware of what kind of week it had been. Many in the audience passed up flowers and cards to the stage and held up signs in honor of Adam, who died of cancer on May 2.
"It has been a long road for David, and we've seen how tough it has been on him," singerRyan Star
, who has toured with Cook since Feb. 14, told People. "I think he's doing the best he can."
Cook opened the show by singing "Heroes," when he raised his guitar to show fans the large black initials "AC" on the front.
Halfway through he sang a few lines from the Eagles' "Hotel California," telling the audience, "Adam would be proud."
| Posted by Lisa Gutierrez, The Star