The rocker was diagnosed with glioblastoma in late 2022.
She coached the Colombian superstar at age 15, when Shak was preparing to sing at Chile's Viña del Mar International Song Festival.
The musician's "Dance Outta My Head" went viral after revealing that all proceeds would go to her seven-year-old son, Loren.
She performed at the famed Tropicana club in the 1940s and '50s and sang alongside artists like Nat King Cole.
The 49-year-old Ukrainian-born piano player died on Tuesday.
"His boundless creative energy has touched so many over the whole world," the group wrote.
Ozawa won Best Opera Recording at the 58th Grammy Awards in 2016 for Ravel: L'Enfant et les Sortilèges.
The musician died peacefully at home of natural causes, his spokesperson said.
"Mojo has left the building," a statement announcing the news on his Facebook page reads.
Over his 40-year career, Kirkup and his partners managed Katy Perry, k.d. lang, Tracy Chapman, Counting Crows and B-52s, among others.
