David Cassidy in Critical Condition with Organ Failure

David Cassidy is in the hospital in critical condition -- his organs are shutting down, and as one source put it, "It's looking grim."

We're told David was rushed to a Florida hospital 3 days ago ... and his condition has been worsening since his admission. We're told he's suffering from organ failure and unless he gets a liver transplant soon he could soon die. We're also told he's suffering from kidney failure.

David, we're told, was in an induced coma but is now in and out of consciousness.

David's family has been arriving at the hospital to comfort him.

The 67-year-old former Partridge Family star has been in failing health for more than 2 months ... this according to sources connected to the family.

We're told doctors have made it clear to the family ... with Cassidy's organ deterioration, they need to prepare for the worst.