For the first time ever, Snoop Dogg and his wife Shante Broadus are opening up about their 11-year-old daughter Cori‘s battle with lupus, which began she was only 6 years old. The rapper tells PEOPLE how he “felt helpless” when after visiting numerous doctors, no one was able to properly diagnose his young daughter’s condition. Read on below:

It all began five years ago when they noticed a light spot on the face of Cori, then 6 years old. Weeks later, the daughter of Snoop Dogg and wife Shanté Broadus was losing drastic amounts of weight and her hair was falling out. Despite visiting countless doctors, no one was able to offer the rapper and his family a diagnosis for little Cori. “I felt helpless,” Snoop told PEOPLE while fighting back tears. “No power, no friends.”

His wife Shanté adds “No one could tell me what was wrong. They drew tons of blood and said she has old-person cells. They gave her all kinds of [medication]. But she went downhill.”

Months later, after getting the heartbreaking diagnosis of lupus, Snoop Dogg and his family began their journey to understand the autoimmune disease, which ultimately brought his family closer together. “She’s the toughest little thing I’ve ever met,” the rapper says of his daughter. “She’s on the honor roll, playing volleyball and softball, living life. She has all this joy. In the beginning lupus was winning. But now Cori is.”

Read all about this in the latest issue of PEOPLE magazine, on newsstands now.