I think asking you for only ‘a drink’ in January is a red flag. After all the time you’ve invested in him, wouldn’t you think he’d at least have asked you for dinner? I know that sounds petty, but it means a lot IMHO.

I’d tell him, when you are in town call me and greatly minimize this pen pal contact.

I also think it’s a red flag that he’s colder when you are not available and asking you about what you are doing. This is all a bit off.