More 2,
You’re questioning his morals and who he is as a person when you admit openly to making up stories without informing the reader (isn’t that the same as LYING?).
It’s great that you care about your cousin enough to want to protect her, and possibly lucky that this guy is coming to your house.
I think you need to approach him with a really open non-judgemental attitude. If you approach the idea of meeting him as wanting to confirm your beliefs then you’ll probably be able to. People see what they look for. Look at him with an ayin tov and you might see positive things.
You have a hard job ahead of you: clearing your pre-conceived notions about him out of your head.