According to reports, R&B star Usher's ex-wife Tameka Foster can't afford to keep her ailing son on life-support much longer as his insurance coverage is about to expire.

Kyle Glover, 11, was declared brain dead last week following a jet ski accident, but Tameka has not lost hope that her son can make a drastic recovery.

But Tameka can only keep Kyle on life-support as long as her insurance company agrees to pay, otherwise she doesn't have the funds to cover the enormous hospital bills.

The insurance company hasn't set a specific deadline, but they've made it clear they're only willing to shell out coverage for a couple months.

Sources say that Usher, who helped raise step-son Kyle for several years, has been supportive in this difficult time but has not offered to pay for any medical bills.

Kyle was struck in the head by a jet ski while inner tubing on Lake Lanier - doctors declared him brain dead days later.