Kyle Glover, who is the son of Usher's ex-wife Tameka Foster, apparently collided with a jet ski on Saturday (July 7) while they were sitting in an inner tube pulled by a boat.
Sources close to the family later claimed that 11-year-old Kyle was declared brain dead after the crash, but no decision has yet been reached on taking him off life support.
The Def Jam co-founder took to Twitter on Sunday (July 8) to express his sadness over the tragedy, writing: "My heartfelt prayers for Tameka and Usher. Can't even imagine... #prayersforKyle."
30 Rock star Sherri Shepherd sent a direct message of support to Foster, tweeting: "My heart hurts for Kyle Glover, @TamekaRaymond's 11 yr old son. Praying for her, Usher & family. #motherlove."
Ashanti also shared well-wishes: "My heart goes out 2 TamekaRaymond thru this indescribable time. Im praying 4 u, Kyle, Ryan & ur family may God bestow his Blessings upon u all."
Usher and Foster were married from 2007 to 2009.