Ahoy, clinical hypnotherapist here. As pointed out above, there are many different flavours of hypnosis. It's not so much that people are hypnotised in different ways; although there are thousands of different ways to hypnotise someone, it all ultimately leads to the same effect; what is important is how the hypnotherapist works with their client under hypnosis.
A lot of hypnotherapists are trained in CBT; in my experience this works well for more logical thinkers and is better than standard CBT. There are hypnotherapists who specialise in DBT too, I've found this approach works better for more creative thinkers. These different flavours both involve the hypnotherapist working with their client under hypnosis to explore and analyse their issues with a view to finding a solution.
There is another flavour of hypnotherapy that is known as solution-based, this cuts the analysis you tend to find with other theraputic approaches and focuses directly on using hypnosis to effect positive changes. So for someone with social anxiety that would be focused around building confidence as opposed to figuring out the root cause.
Unfortunately, hypnotherapists are like ordinary therapists in the respect that some are very much better than others. I hear of people who struggled to be hypnotised and therefore assume that they absolutely cannot be hypnotised at all but this is rarely true, a good hypnotherapist worth their salt has many different tools they can utilise - for extremely anxious people I have (with permission) used what are known as rapid inductions, that results in achieving a state of hypnosis and relief from their nerves very quickly; other nervous people may require a far more gentle approach whereby the whole first session is dedicated not to any theraputic purpose but simply to allowing the client to experience hypnosis and relieving them of any myths they may harbour such as the fear of losing control - contrary to the movies, being under hypnosis isn't like going to sleep and nobody can force you to do anything against your will or without your knowledge.
Unfortunately, hypnosis was ignored by mainstream therapists for many years and is still treated with disdain by many, but it's recently been gaining credibility as both an enhanced form of traditional therapy and a therapeutic framework all of its own.
I suspect that between my years as a stage hypnotist and as a hypnotherapist, I've hypnotised just about every kind of client there is; if your friend can find the right hypnotherapist then they should be able to derive a lot of benefit from that.
Don't be tempted just to pick the first person who pops up on Google, do your research and find the right fit. It sounds obvious but so many people miss this step.
