Sharon Osbourne has slammed her estranged brother in an open letter, accusing him of attempting to cash-in on her son Jack's Multiple Sclerosis battle.

The X Factor judge and her brother David Arden fell out following their father's death in 2007, and relations between the siblings have remained distant ever since.

On Monday (02Dec13) Arden, who is also an Ms sufferer, told Britain's Daily Mirror newspaper he was desperate to help his nephew but he can't get close to the family.

His public plea did not go down well with his sister, who has taken aim at him in an open letter posted to her Facebook page.

Sharon has accused Arden of trying to make money from her dysfunctional family.

She writes, "Now, you appear again, having sold a two-part story to the Daily Mirror, claiming you want to help Jack with his Ms. That’s as low as it gets, making money off my son’s Ms.

"Jack was diagnosed in 2012, where have been the last 18 months? You know how to reach me. You know how to reach the Osbournes."

In the lengthy post Osbourne also claims to have repeatedly given her brother financial support and reminds him of his previous arrests for drink and drug offences. She closes the letter by revealing she has instructed her lawyer to get involved in the family feud, but insists there is no point in suing her brother as he has no money.