Joan Rivers -- On Life Support ... But Family Remains Hopeful

Joan Rivers is on life support ... and sources close to the legendary comedian tell TMZ she is completely reliant on machines to stay alive.

According to our sources, the family will have to decide in the next couple of days whether to keep the 81-year-old on life support. We're told the family remains hopeful that if they do decide to turn off the machines, she will make a turn for the better and fight through it.