Hello hope you're well. Sorry you've had to go through that and also sorry for your loss. First thing I would say is try not to be so hard on yourself about how things ended. You've nothing to forgive yourself for. The last days and hours of someone's life is never going to go the way you'd want or expect. Everyone has their perfect idea of how they want to say goodbye. There's loads of reasons he was how he was , medication can play a massive part in it as well( so I'm told) maybe he just didn't want you seeing him the way he was at that moment, but there's nothing you have to be sorry about. 

I don't really have a similar situation in regards to the final moments, but the last maybe 6 months , she felt funny with any physical contact. During her chemo I'd give her massages to help with the numbness in hands and feets then like a light switch she wouldn't want that or any cuddles or whatever. We had a chat about it and something she told me was it was as if she was going into self defence mode. "If I don't get close with anyone then it won't be as hard on them when I go"  someone on her weekly teams support call told her about the self defence thing and it broke my heart hearing her think that it would somehow make things easier when she eventually passed away. I know it's not the same situation but maybe something in that that's the same ? I don't know. 

I have a brass neck telling you not to overthink anything. I suffer from OCD and the last few months have consisted of me writing down full conversations we had, reading over texts. Going over our full relationship and wondering if something I said one day was taken the wrong way (I know it's weird) but lie you said yourself, you were there for his last breath. And I know it would've made it a whole lot less scary that you were there. Hope that somehow helps. 

Again sorry for your loss and I hope you're feeling okay today. 

I also hope the nightmares start easing off. Alot of people just pass them off because they're "not real" but the feelings we get when waking up from one is horrible..I keep having one where we're in a dark hospital and she's on the floor with a blanket and I can't get the image out of my head. Makes me feel sick for hours after I wake up 

Thank you JD1991