Expect this week's performance to be more emotional than usual for American Idol favorite David Cook.

And, no, it's not because he's an especially huge fan of guest mentor Mariah Carey.

David's brother, Adam, will be in attendance during tomorrow night's live broadcast. As became known two weeks ago, Adam is suffering through his second diagnosis of brain cancer.

The Terre Haute Trib Star has an article about the brothers live on its site. Here's an excerpt from it:

It was a dream come true for a Terre Haute man as he and his wife left a cold and blustery Hulman Field on their way to California on Sunday.

Wearing a Valparaiso University Law sweatshirt and a navy baseball cap, and waving to friends and family, Adam Cook, with the help of a cane, boarded the Leer jet that would take him almost 2,000 miles to watch his brother, David Cook, attempt to become the next American Idol.

The trip nearly didn’t happen.

Adam Cook, 36, is undergoing chemotherapy for his second diagnosis of brain cancer, which has spread to his spine. A plan to travel to California to see his brother perform was grounded earlier in the week when Adam’s doctors told him he could not fly commercially in his condition.

Read the full article on Adam Cook now.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.