11-year-old Glover died on July 21 from injuries sustained when he was struck by a jet ski while sitting in an inner tube on Lake Lanier.
Usher – who previously said he was "torn up" by the tragedy - seemingly referenced Glover's death during his set at the Apollo Theater benefit in the Hamptons on Saturday (August 11).
"For all the hard times, you can't do it without your friends, so I just want to toast a second . . . Thank you for allowing me to share this incredible moment with you," Usher said, adding: "Cheers for tears."
Paul McCartney and Jennifer Hudson also helped raise $2m for the legendary venue at the benefit show, reports Page Six.
Usher is still involved in a custody battle with Glover's mother Tameka Foster, who previously claimed that the singer's sympathy for her loss is simply a ploy.
Their child custody battle will apparently not be affected by Glover's passing.
Watch Usher's 'Burn' music video below: