Is there proof for the effectiveness of sound healing?
No, there is no sufficient evidence for sound healing. Sound healing is pseudoscientific alternative medicine. Examples of this would be singing bowl therapy which uses Tibetan singing bowls, it's proclaimed that these can create a meditative state or a healing state from the vibrations, however there is no evidence to this claim.

However, there is legitimate uses for sound as therapeutical support. This is known as music therapy and uses different varieties of music to promote a positive physical and mental health response. This can be in the response of lowering the patients heart-rate or assisting with depressive disorders.

Music therapy has seen particularly good results in several medical disorders such as autism and dementia. There is also evidence that it can be beneficial for those diagnosed with PTSD, where music therapy is commonly employed by soldiers in the military, be it active duty, veterans or family members.

Whilst there is no such thing as sound healing, there are most certainly medical uses with music that are widely recognised and used throughout the world.
you have a good answer here but i must say that music can just make people more relaxed lowering heart rate so it can help mitigate certain disorders in the long run maybe not heal them but helping them to pervert certain disorders such as ones that result from fast heart rate.
This can be true, but none of this means medical treatment. One's mood, stress level or general condition can be influenced a lot of things, which has nothing to do with medicine, more like every day life events and problems.
You're right. We should define our terms about what we mean by medical treatment. If it means anything beneficial to health then maybe sound healing could be considered medical treatment, but if we mean a direct treatment for a specific problem, then sound healing is just a complete sham! I think that the second is a better definition.