DMX's health is rapidly deteriorating as he remains on life support, with not much more doctors can do ... and he's experiencing significant organ failure.

Sources with direct knowledge tell TMZ ... as of Friday morning, X's "organs are failing by the minute" ... a sign, under the circumstances, indicating end of life. We're told friends and family have been told to fly in immediately to be with DMX and his loved ones.

As we told you, X's mom, fiancee, kids, ex-wife and mother's of his children have become a tight unit over the last week, staying and praying together ... holding out hope, although hope is clearly waning.

TMZ broke the story ... DMX, who remains in a coma, underwent a series of brain function tests Wednesday, and sources told us the results were "not good." He has not improved since he was rushed to the hospital with "little brain function." Our family sources say the final decision, if and when it happens, to take X off of life support will be made by his mother, Arnett.