From PEOPLE Magazine Click to enlarge
Nelly's getting horizontal in here. Slumped on a couch in a New York City music studio, the rapper—who has been awake for two days straight prepping his two upcoming albums and shooting a film in New Mexico—can barely keep his eyes open. His couch-mate, sister Jackie Donahue, adjusts her pink head scarf as she playfully pokes him awake. "My brother never rests," she says as Nelly sinks further into the couch, his head resting on her shoulder. "But when I'm in the hospital, I get enough rest for the both of us."

Donahue is happy to give her brother a shoulder to lean on: He has been doing the same for her ever since she was diagnosed with acute myelogenous leukemia in 2001. Soon after her relapse last year, the rapper (born Cornell Haynes Jr.) formed the Jes Us 4 Jackie campaign to find a bone-marrow donor for Donahue, 31, and raise donation awareness, The best chance for a donor match comes from one's own ethnic group, but of the 5.4 million people registered with the National Marrow Donor Program, only 429,758 are black. Since Nelly's charity organization 4Sho4Kids began sponsoring the drives—there have been eight so far—1,722 new donors, many of them African-American, have registered. "First, you got to get the people in. That's the hardest step," says Nelly, 29, "and we've been able to do that."

Yet despite Jes Us 4 Jackie's efforts, Donahue—who suffered another relapse in June and then had an adverse reaction to her new chemo drugs—still hasn't found a match. "It just hasn't happened for us yet," says Nelly, who has been tested himself but isn't a suitable donor. Helping others in her situation, adds Donahue, a single mom to Shawn, 13, and Sydney, 7, "is what really keeps me going."

That and Nelly's encouragement. Working together on the drives, "if s almost like a rediscovery for both of them," says Nelly's aunt Chalena Mack. The half siblings, who both live in St. Louis, share the same father, Cornell Sr., 53, but were raised in separate homes. Now their own kids—Nelly has a 10-year-old daughter and a 5-year-old son—are growing up together. "They all fight like sisters and brothers!" says Donahue. Adds Nelly: "My daughter listens to what I allow her to listen to. I like to censor. They're hip-hop kids; they have no choice."

As a family unit, they help each other cope. "Sometimes I call him crying on the phone, ready to give up," says Donahue, who worked as Nelly's stylist before she was diagnosed. "He makes me think about positive things." When she lost her hair during a monthlong July hospital stay for another round of chemo, Nelly cut his off too.

Nelly's music will take center stage again on Sept. 14, when the rapper releases two albums: the up-tempo Sweat and the sultrier Suit (his performance of Sweat's "Tilt Ya Head Back" with Christina Aguilera was one of the high points at last month's MTV Video Music Awards). Despite Donahue's plight, Nelly's new material continues in the party vein of his hit song "Hot in Herre." "I still love to have fun for the music," he says, "because that's what got me to this point."

And beyond. He's branching out professionally, playing a running back alongside Adam Sandler and Chris Rock in The Longest Yard, a remake of the 1974 gridiron film, due out next May. Though Nelly has never taken acting lessons and his only prior role was as a rapper in the 2002 indie movie Snipes, "my mama says I've been acting my whole life!" he says with a laugh. Maybe so, but filming Yard with Sandler and Rock, "it's hard to keep a straight face," he says. "You know what they're supposed to say. Instead, they shoot something else at you! And you're like, I'm supposed to remember my line after that?' "

He recently also fulfilled a lifelong dream by becoming part owner of the Charlotte Bobcats, the new NBA expansion team. "If you asked me five or six years ago where I'd like to be," says Nelly, who's currently single, "I'd say this is where." All that's left for him to do is give Donahue a happy ending. Next year, he predicts, "I'll probably be sitting here, saying we found a donor." Adds Donahue, looking at her yawning brother: "Then he'll take a good, long nap."

Jason Lynch. Natasha Stoynoff in New York City

  • Contributors:
  • Natasha Stoynoff.