Hello Akrasia,
At the same time, I can't cope with any more of the "oh my god angel queen marry me" and then the "why are you contacting me and putting pressure on me"? Then round and round some more.
I couldn't cope with it either. It's crazy-making. IMO you should back off, be his friend on terms that don't drive you nuts
if that is possible, don't depend on him as a romantic partner. He's shown he's not dependable. Too many really deep issues. Not through any fault of his own but unless he faces them and seeks healing, well, he'll just continue as he is or get worse.
I do not mean to sound unfeeling about his loss and other traumas he faced, and is still facing. Yes he needs support for this but it doesn't have to be all you. If you're not up for it - and it sounds like you're not - then that is your truth and he needs to accept it.
I have a friend who could be equally draining. He was never a romantic consideration, ever. He is also from a different country. Years back, I used to try to help him with emotional support and I helped him navigate paperwork. But - his life is one drama after another, he goes on endless rants about all the injustices he feels life has heaped on him. He seems to love being a victim and complaining endlessly. I stopped paying attention. I still care about him and we do still have pleasant interactions but as soon as it devolves into his litany of complaints, I'm out.