Is the olive leaves really helpful for diabetes (ofcourse as the dr prescribe it with medicine)?

No, Not that I know: Diabetes has many treatments but Olive Leaves are not known to be an established treatment. I would question the wisdom of using such alternative or complementery therapy.

Doubtful: Many products including cinnamon have been touted as treatment for diabetes but scientific proof is lacking. Exercise and reduced carb and calorie -intake will likely do you more good.