Yes the pin will probably fit and he will be able to hook on (the only way to know for sure is measure both).
But
If the trailer is built for a single axle truck and your buddy has a tandem, you might not be able to turn with out hitting his mud flaps on your landing gear. Might be able to slide his fifth far enough back to make it work.
He probably has air brakes and probably doesn't have a controller for electric or hydraulic brakes, so if the trailer has a park brake of some kind, you might have to disable it to move it and you won't have any trailer brakes. His truck would probably have enough braking power to be safe running mt, but probably not legal.
He probably has a 7 pin round light connector, the trailer probably has something else. So you will need an adapter of some kind.
He probably has a commercial plate on the truck and makes a living with it, Pulling a trailer with no brakes, no lights, and no safety, may be more risk then he is willing to take.
If it was me with my own tractor, and I didn't have to go thru a check stop, I would probably clean it up the best I could and have at er. If I had to use one of my company trucks, $200.00 would be a bargain.
it looks like a decent trailer, a litle TLC and you're on the road
gm