Barry King / WireImage 1 / 14
Barry King / WireImage 1 / 14

After a home invasion last year, Mariah Carey's sister Alison was picked up by police after being spotted "wandering in the street barefoot and partially dressed."

Their brother, Morgan, says Alison's behavior stemmed from brain damage Alison suffered during the attack and from Alison, who has worked as a prostitute and has been HIV positive for many years, failing to take her medication.

Both of Mariah's siblings are hoping their successful sister can cover the cost of Alison's health care, a request they recently made public with a video Morgan recently with the Daily Mail that details the situation.

The video shows Alison saying "yes" three times as her brother asks "are you Alison Carey" and if the date when the video was shot was Sept. 15, 2015. Morgan then asks Alison if she wants to revoke the do not resuscitate form another family member has signed in regard to Alison.

Alison says "I do."

According to the Mail, Morgan has asked Mariah to step in and pay to help Alison, who has struggled with a drug addiction that led her to blow much of the $1.6 million her father left her when he died in 2002.

The video suggests Alison wants Mariah's support, too.

"Mariah I love you, and I desperately need your help," she tells the camera, "please don't abandon me like this."

For years, reports have pointed to the assistance Mariah's given her ailing sister. The soon-to-be-remarried singer has covered the cost of Alison's rehab multiple times, according to Fox News. But the pair seem to have been on bad terms since a massive fight in the mid-90s.

"Through the years, Mariah has spent hundreds of thousands of dollars supporting Alison and her children," a rep for Mimi told the Mail. "In fact, Mariah has supported her extended family for over two decades."

Things don't seem to be much better between Mariah and Morgan. A few weeks after she was institutionalized following the street wandering incident, Alison was released from the hospital. According to Morgan, she now needs more expensive care.

"Because Mariah has not found it in her heart to help Alison get the care she requires there are times when Alison forgets or is unable to take her medication and this sometimes precipitates problematic

behavior," he says, adding that Alison's brain scans "show severe damage."

"Mariah is the one person in the family who could actually make a real meaningful difference to Alison's life. The least she could do is put Alison in a good hospital and make sure she gets the care she needs."

Recalling that neither Mariah nor Alison's mother joined him at the hospital when she seemed likely to die, Morgan also tells the Mail "the worst is yet to come" for Alison and that because Mariah's "fiance [James Packer] is a billionaire" they should "step up" and help.

He adds that Mimi shouldn't worry about potentially enabling Alison's drug habit because it's "simple" to safely "make sure that [an addict's] basic medical care."

It's not the first time Morgan has aired the family's proverbial dirty laundry in the tabloids. Earlier this month, he told The Sun Alison had tried to contact Mariah about the brain and spinal surgery she needs but had not heard back.

Last year, he told the National Enquirer he believed his sister was bipolar and an alcoholic.

Mariah, meanwhile, has been on tour in Europe this month. The singer, who's currently sporting a massive engagement ring estimated to be worth at least $7.5 million, is rumored to be planning a wedding with her fiance in Barbuda.