I feel like I'm going on a rant today about M&H talking about mental health, but tbh they say so many harmful and wrong things, I may as well get it all out lol.
I was perturbed to see Harry platforming Gabor Mate. Mate's not a clinical psychologist, he's got lots of odd and controversial ideas about biopsychosocial approaches to trauma which are not largely agreed with, and he also advocates the use of hallucinogenics to treat trauma, which, despite the fact that it seems to be fashionable among celebs atm, is a potentially highly dangerous way to attempt to 'treat' people with PTSD. Why Harry thought it was a good idea to give his 'watershed' mental health interview with Mate, I don't know. He's not mainstream at all, it would be like doing an interview about the role and function of the British Home Office and choosing David Icke as the resident expert.
I haven't looked into what Kate and William do about mental health but I did see an interview with her on the news a few years ago, on the subject, and she was talking about CBT, the importance of social networks, the importance of exercise, you know basic bread and butter stuff for mental health that is mostly accessible to the masses, not just the privileged. That is a LOT more helpful than Harry doing an interview with Mr Drop Shrooms and Run Naked Over the California Mountains Ululating Gabor Mate.