There is clear trauma in Harry, of which is completely understandable.
I'd wage PTSD, more so from ACES than combat, but both can contribute. He probably also has a BPD. Narcissistic personality disorder maybe, PTSD and PBD can go hand in hand.
Problem with PTSD sometimes it can manifest and present as a inability to trust and paranoia.
Some of the sweeping statements H makes sorta "fulfill" this. He has a deep routed belief that The Royal Family are out to get him and Meghan. That the British press want to kill Meghan.
These are clearly very unhealthy thought cycles, and I do worry without the appropriate help, these will cycle over and over again.
Meghan strangely has also become "the model of my mother, the model of my trauma" which will intensify those feelings of distrust, paranoia and overall trauma response.
He's become fixated on Meghan and her safety, borderline compulsive about it, and he probably doesn't even acknowledge this.