Usher's ex-wife says he didn't care about her dead son.

The OMG hitmaker was devastated when Kile Glover - the 11-year-old son of his ex-wife Tameka Raymond and her former partner Ryan Glover - died from heart failure two weeks after being left brain dead following a jet ski accident but Tameka insists he is merely trying to win sympathy.

She is locked in a bitter custody battle with Usher over their kids Usher Raymond V, four, and three-year-old Naviyd Ely Raymond and says his request to delay the next hearing in their court case is merely a "transparent sham".

In court documents obtained by gossip website TMZ, she alleged "[Usher] visited Kile in the hospital only once."

She asked the judge to deny Usher's request and force him to appear at the next scheduled hearing, set for August 13 claiming that resolving the custody battle is the only way she can move forward.

Usher had requested the postponement by insisting a court date would cause "unnecessary stress and strain" for the former couple and their two children "in the immediate wake of this tragedy".

He also claimed she would get an unfair advantage in the hearing because the court would not want to rule Tameka so soon after the death of her son.