Driver Side Door Sags, Air Rushing in

05 Jeep Grand Cherokee Laredo, the top driver side door hinge top nut&bolt are not flush with door. (Causing the door to sag)

When I went to tighten the nut it does not tighten up at all (it will spin and get a little tight, then loosens back up and just spins)

Does the bolt the hinge sits on need to be replaced, or can I put a washer or two behind the nut to see if it tightens up?

Or is one or both stripped? If so, how do I replace just this one bolt&nut; so I am not replacing an entire hinge? As they do not look bent in any way, the top hinge just isn't flush with the door itself (not body of the car).

Thank you.