{blackbabes} Mel Gibson Invited to Whitney's Funeral ... He Tried to Save Her

Mel Gibson was invited to Whitney Houston's funeral ... and the family extended the invite because Mel tried to help the singer during a very dark period in her life ... TMZ has learned.

Sources tell us ... several years ago, when Whitney was about as bad off with drugs and alcohol as she ever was, Mel quietly intervened and spent a lot of time with her, trying to help her break the addiction cycle.

We're told Whitney's family is "extremely appreciative" and wanted Mel at tomorrow's funeral, but because of family plans he can't attend.