Wikipedia

Steven Hayes’s A Liberated Mind goes into this a little bit. Basically, if you are psychologically flexible and your interactions target the psychological flexibility processes, you will create the best conditions possible for change. For example, if you notice they are adopting a conceptualized sense of self tied to failure, then you could point it out: “It sounds like you think you are destined to fail”.

If that book is too long or complicated, you can check out What Makes You Stronger, where the DNA-V model is laid out. DNA-V is a simpler and perhaps more intuitive way of understanding the psychological flexibility processes. Once again, you first want to psychologically flexible yourself. Then, you want to (tactfully and when appropriate) point out the advice your friend’s brain is telling them; have them notice their inner experiences and perhaps their outer experience; and establish what matters to them and how to explore/discover routes towards that.

Another book that touches upon this, but from a different point of view is Never Split the Difference. While it’s written from a bravado and a hostage negotiation point of view, if you read it with critical eyes, you can learn a lot from it. Being a mirror for others, addressing fears head on in a tactful and compassionate way, and asking calibrated questions can be helpful.

I’d say that, more important than applying specific change techniques, it’s most important for you to be psychologically flexible so that you can be present and compassionate with your friend. Only then can anything else flow.