Male 25M friend of GF 24F coming from overseas to stay over the weekend...

So my gfs friend (dating 9 months now) is coming from overseas for a trip and will come stay over at her parents place, ofcourse in different room. I am invited to go pick the guy up with her but I have never met him before and have no idea who he is. She met him at college when she went overseas. Says he is cool and I have kept my calm but I am defintely not sure about this. I do trust her with all my heart but I am confused why would she put me in a position like this .

She mentioned couple times over the year this guy will come maybe and I always gave a neutral repsonse but now that the guy has booked tickets and all I am not sure how to proceed. He will stay 2 nights at her parents place with her being there as well. She said I can come sleep there as well but it would be untrustful behaviour if I do that is what I feel. Plus I never prefer staying overnight at her place when the folks are around.

Am I insane to worry about this?