Alfred Adler did not use "metaphor therapy," if by that term you mean the use of metaphors as the primary focus in diagnostic and treatment strategies. He was very creative in treatment and used whatever technique seemed appropriate to each client. Being "creative" implies the invention of strategies that can capture the uniqueness of each individual, and that facilitate each stage of treatment. For this reason, in the Classical Adlerian approach, we use a variety of cognitive, affective, and behavioral strategies that might include: the Socratic method, eidetic and guided imagery, role-playing, bibliotherapy, dream and daydream analysis, as well as metaphors.
Metaphors can frequently be used by clients to intensify negative feelings and avoid common sense. Countering a negative metaphor with a positive one, usually offers some encouragement, but unless the underlying goal and style of life are modified, any affective or behavioral changes may be superficial and temporary.