Johnny Lewis' Dad -- I Exhausted All Resources To Save My Son

Johnny Lewis' father tried to help his son multiple times before his death ... telling TMZ he believed Johnny's last stint in a treatment center was finally going to work.

A close family source of Johnny's tells TMZ that Johnny tried a few different Scientology approved treatment center, but they didn't work.

So Johnny's father, Michael Lewis -- a high level Scientologist who was once close to L. Ron Hubbard -- tells TMZ he then turned to a treatment facility in Altadena, CA called Ridgeview Ranch as a last resort. Ridgeview describes itself as specializing in the "treatment of mental heath and/or drugs and alcohol."

Michael tells us that Johnny responded well to the environment at Ridgeview -- the staff was supportive, the program seemed to be working and says he thought "it would stick this time."

Michael says that Johnny's treatment physician at Ridgeview advised against the use of psychiatric medication (which is highly frowned upon in Scientology) and used an alternative approach to getting well.

However, after a short stint at Ridgeview Johnny opted to finish the rest of his sentence in jail ... insisting he had no drug or psychiatric problems.