I honestly don't think we have enough information to conclude that Harry has mental health issues or that Meghan is controlling (which is a serious accusation). Interestingly the only part of their 'story' that is at all positive is the relationship between them - which is - if we're to believe what we're told / shown - is very loving and happy. Maybe that bit's true. I hope so for them and their children.
I do think it's not really fair and a bit of a problem to attribute bad behaviour to mental health problems every time as if it's an excuse. Because that implies abdication of responsibility, which I don't think itself is very mentally healthy.
It's not an excuse - especially for causing other people security risks in an entirely avoidable way - and it's insulting to people who have mental health problems who manage to not be total dicks. Most people who suffer mental health problems manage their problems without destroying everyone else. He has resources of which most people can only dream. He could have checked himself into a residential therapy centre, not published a book.
If we're going to go down the 'mental health is an excuse' road, then surely that could apply to the Taliban too, most of whom will have grown up in far worse conditions than Harry? But that's not ok is it, it doesn't excuse what they're doing to women and girls.
M&H have spoken about how badly the press twist things - surely it doesn't take much brain power to see how this was going to go. They seem to have 0 self awareness, it's really bizarre, they just can't accept any outside view that isn't 100% in compliance with their thoughts. Their complaints about Notts Cott for example - that's a dream home for a large proportion of the population, did they really not see how complaining about living in luxury (for most), whilst child poverty, food bank usage etc is at a record high in the UK would go?
It's not benefiting Harry to be in this position where he can't accept criticism or advice and it reads to me as spoilt (for which the RF do bear some responsibility) rather than unwell. Hopefully this will be a watershed moment and he'll actually engage in some true self reflection after this and try to not do any more damage (e.g. by not coming to the coronation).