Usher's former stepson seriously hurt

Usher Raymond, pictured here, was married to the mother of critically injured 11-year-old Kile Glover for two years.

• Kile Glover, 11, suffered a serious head injury when a jet ski hit him Friday
• Usher was married to Kile's mother and is the father of his two young brothers
• "We know God's in control," Kile's family says
• The child's father is Bounce TV President Ryan Glover

(CNN) -- The former stepson of singer Usher Raymond remained in critical condition in an Atlanta hospital Tuesday, four days after he was injured while riding in an inner tube at a north Georgia lake, his family said.

A personal water craft crashed into Kile Glover, 11, and a girl as they rode on an inner tube that was being towed by a pontoon boat in Lake Lanier on Friday, according to an accident report from the Georgia Department of Natural Resources.

Kile suffered a serious head injury and was flown by helicopter to Children's Healthcare at Egleston Hospital in Atlanta, it said.

The 15-year-old girl, who was not identified in the report, was also taken to the hospital. Her condition was not made public.

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Jeffrey Hubbard, a 38-year-old Atlanta man, was driving the personal water craft, the investigation report said. Investigators concluded that alcohol was not involved in the incident.

The family has held vigil at the hospital since Friday. Usher visited Kile early Saturday morning, but has not returned, according to a source close to the family.

"We know God's in control, and are leaning on our faith in Him and His word at this most difficult time," his family said in a statement to CNN Tuesday. "We firmly believe in the power of prayer and ask that you all continue to pray and lift Kile up, as it's the best way we can all support him now."

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Kile's mother is Tameka Raymond, who was married to Usher for two years until their divorce in 2009. The couple have two sons together, ages 3 and 4.

Kile's father is Ryan Glover, the president of Bounce TV, a fledgling television network targeting African-American audiences. He is also a former executive with Turner Broadcasting, the parent company of CNN.

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CNN's Dave Alsup contributed to this report.