Connection to another person....

[Meerie]

Yeah I have felt this, too, and sometimes even before meeting the person, just from talking to them in cyberspace.
Something "clicked" and there was instant and easygoing connection.
He may be a member of your soul family, or someone you had a past life with.
if you became friends and connect so well, as you say, I am rather sure he feels it too.
No reason to mention it to him, though, if it makes you feel unwell.
I would say, just enjoy the feeling of having found someone with whom hanging out is so easy and familiar.