Barry King / WireImage 1 / 10
Barry King / WireImage 1 / 10

The Carey siblings are at war.

In an effort to reach sister Mariah Carey, her big brother Morgan spoke to Britain's The Sun to lash out at the pop diva for failing to pay a new round of medical bills for their ailing sister Alison, a former prostitute who's HIV-positive.

"Your sister is dying and she is struggling and where are you? You think you are so fabulous, but you are a witch," he told The Sun on March 12.

According to Morgan, millionaire Mariah -- who got engaged to Australian billionaire businessman James Packer in January 2016 -- has ignored pleas to pay for Alison's treatments as her health deteriorates.

"Mariah needs to step up," Morgan said. "I flew in from Hawaii last year when Alison was taken off a ventilator, believing she was going to die. My sister [Mariah] didn't even show up at the hospital."

"Thankfully, Alison had a miraculous recovery, but now she needs brain and spinal surgery and will be going into hospital any day," he added. "Alison has desperately reached out to Mariah over and over again. We never hear back."

Morgan also attacked Mariah's devotion to her beloved Jack Russell terriers, alleging that "She probably spends more on dog food than it would cost to make sure her sister gets properly cared for."

He also branded Mariah heartless after she ignored him when he shared some sad news with her. "I told Mariah my wife had miscarried and she never even responded to that email either," Morgan told The Sun.

"But that's typical," he added, "because the world has to revolve around Mariah and there is no room in the world apart from her."

It's not the first time Morgan has publicly criticized his famous sister.

In 2015, he alleged that Mariah has been a heavy drinker since she suffered a mental breakdown in 2001. "I can't say that I have ever been around her when she was sober, and that's very scary," he told the National Enquirer (via MailOnline).

The same year, the National Enquirer confirmed that Mariah and her sister were estranged, but also made it clear that the pop superstar has repeatedly helped her troubled sister for decades.

"Although their relationship has been strained since they were young, Mariah supported Alison and her children on and off for years," a source told the tabloid.

"She also helped pay for Alison's drug rehab as well as her treatment when she was diagnosed with HIV in the 1990s," the source continued.

"But a vicious dispute over the responsibility and care of her children, her call-girl lifestyle and Alison's attempt to write a scathing tell-all book about Mariah and the Carey family has led to an estrangement of many years."