Britney Spears' Manager and Lawyer Left In Charge of Her Care

Britney Spears has lost most of her support system to help with the care she desperately needs ... leaving her lawyer and manager essentially in charge of her well-being.

Sources with direct knowledge tell us it isn't necessarily a case of Mathew Rosengart and Cade Hudson taking the reins ... it's more they're the last people standing in Britney's life.

We're told they assist in getting Britney fed, to appointments and manage any potential professional opportunities that may come her way.

Our sources say Rosengart does not believe Britney's mental state is cause for great alarm, and there has been no plan to amp up her medical care and therapy. Some folks in Britney's world don't see it that way and believe she's in desperate straits.

As for her family ... Britney's very publicly shut her dad, Jamie, and sister, Jamie Lynn out of the picture. Her mom, Lynne, flew to L.A. a few months ago to help her daughter, but that relationship has since fallen apart as well.

Our sources say Britney's older brother, Bryan, has occasionally been trying to help Britney since her split with Sam -- going to her house to workout, and offering to do what he can -- but we're told Bryan's walking on eggshells, as Britney's just too volatile.

Britney threw a small divorce party over the weekend. She wore a green dress and surrounded herself by a bunch of shirtless dudes -- including Cade Hudson.