Things went from bad to worse for Kyle Glover, Usher's 11-year-old stepson after a tragic Jet Ski accident left the youngster in critical condition on Friday, doctors have now declared him brain dead. TMZ is reporting that Glover, who is the son of Usher's ex-wife, Tameka Foster, has not experienced any brain activity since he was admitted into the hospital two days ago. According to reports, the pre-teen and a friend were floating in inner tubes on Lake Lanier in Atlanta when they were struck by a man on a Jet Ski. Glover was unresponsive when he was taken out of the water and airlifted to Children's Healthcare of Atlanta at Egleston; his friend, an unidentified 15-year old girl, was treated for a cut on the head and a broken arm. According to the Atlanta Journal-Constitution, the Georgia Department of Natural Resources said that alcohol doesn't appear to have been a factor in the accident and the newspaper also reported that the man on the Jet Ski and Glover were part of the same group on an outing at the lake. Foster and Usher (born Usher Raymond) were married in 2007 but divorced in 2009. The two are reportedly both present at the hospital. Many of Usher and Foster's celebrity friends took to Twitter on Sunday (July 8) to express their deepest sympathies. "My deepest prayers go out to Tameka, Usher and both of their families right now," Diggy Simmons wrote. "Wishing @TamekaRaymond's son godspeed recovery. horrible news to hear," Roots drummer Questlove added, while television personality La La Anthony wrote: "Praying for @TamekaRaymond and her family. Asking to give her and her family strength during this difficult time. Praying for u Kyle." This tragedy comes a month after Usher released his latest Number one album, Looking 4 Myself.