Yeah, it's the old "in theory" thing.
In practice trying to rig from the centre of your vehicle out to one side or the other then back down to the stranded vehicle is almost always impractical due to not having enough snatch blocks, winch extensions etc .
Put it this way, with a standard length winch cable, one or two snatch blocks and one vehicle behind the other it just is not going to happen.
You are going to have to rig forward at a small enough angle to not side load your winch OR use a snatch block redirect to get to the side THEN, another snatch block to redirect back and I would suggest at least 1 probably 2 more to redirect onto the front of the stranded vehicle and/or clear the ground
That is a lot of cable and blocks and you still have only 1:1 line pull
One option would be rigging his vehicle to the rear of yours and winching/driving in concert using the gear on your vehicle to give you a 4:1 advantage on your winch.