Ask your LOR. Maybe if the guy really doesn’t have another ride then the rabbi can arrange something.
This guy who needs a ride isn’t the first guy in history to need a ride. Even if it seems like there is no other option, there could be but it just hasn’t unfolded yet.
Plus maybe the rabbi knows of another solution for the guy and it leaves you and the question of yichud out of the equation. Wouldn’t that be preferable?
If you don’t follow the rav or put yourself in a spiritually impure situation, then there really is no mitzvah of giving this person a ride and it won’t even help him, would it?