[1] https://www.reveri.com/ [2] https://hubermanlab.com/dr-david-spiegel-using-hypnosis-to-e...
Yes, depression has been cured by hypnotherapy. But you have to find someone who knows what they are doing. Even most professional hypnotherapists don't really know what they're doing, so your friend shouldn't be afraid to try different ones until they find someone effective. I suffered from depression and was cured by a hypnotherapist, but he is arguably one of the greatest therapists in the world. Meeting him wasn't cheap, but it gave me my life, so it was literally priceless. Not every therapist can do that. (Although the guy spends a large amount of his time teaching seminars all over the world to transfer his knowledge, yet his work is called "pseudoscience" and ignored or dismissed by academia.)
Based on your guitar and hocus-pocus comment I reckon that you know about as much about meditation (guitar or not) as a Chicken Soup For The Soul reader knows about theology.
> I'd say that the main difference
Is definitely the practices themselves.