@Cece92 I would approach this one with maximum caution and zero expectations.
If what he says is true, for a start he's been through some massive life changes and is struggling with depression and grief.
However whatever peoples' struggles are if they like you enough, they will try to meet you.
I had a few situations like this during lockdown because it was really hard to meet people irl. However I think that it also increased the number of future fakers and dreamers that I was prepared to have in my life. They'd often make vague plans to meet, then flake. They'd also always have some personal crisis going on.
The problem is when you don't meet these guys but you're always prepared to be there at the end of the phone or a video call, they'll keep coming back because they're getting the girlfriend experience without actually having to put the work into having a girlfriend.
From your side this sounds like limerance or maladaptive daydreaming.
What's going on in your life that means you'd be prepared to have a virtual relationship for this long? Do you have other friendships or hobbies that keep you busy? Do you think you're avoiding something by staying in this 'not in real life' experience? Are you trying to protect yourself?
Some people are content with a virtual relationship. Are you? How would you feel if you never met this guy but carried on chatting for another four years?
Caveat: I'm assuming that you haven't sent this person any money and that it's not in any other way abusive.
Obviously if he comes over you should meet him. That might help you pierce the bubble. Otherwise I would seek help and support from friends and maybe a counsellor, to move on from this.