The former Partdridge Family star was admitted to a Florida hospital three days ago and is suffering from organ failure, according to Page Six.
It has also been reported that he has been put into a medically induced coma.
A rep confirmed, “This is true. He is conscious now and surrounded by family.”
The 67-year-old actor and singer is suffering from kidney failure and needs a liver transplant, according to TMZ, with a source also confirming to the website that his prognosis is ‘grim’.
His family have been told to prepare for the worst and the gossip site says they have gathered at his bedside.
David is best known for his starring role as Keith Partridge on the 1970s series The Partridge Family.
In February, the star revealed he was battling dementia after he fell on stage during a concert in Los Angeles.
His mother, actress Evelyn Ward, and his grandfather also had the condition.
During the concert, the star tumbled on stage and forgot some of his words, prompting fears he had started drinking again.
He told People magazine after the gig: 'I was in denial, but a part of me always knew this was coming.'
I want to focus on what I am, who I am and how I've been without any distractions,' he added. 'I want to love. I want to enjoy life.'
David’s life hasn’t been without trouble, he has filed for bankruptcy, divorced from third wife Sue Shifrin, has had multiple arrests, eye surgeries and went through a stint in rehab.