Fighting games don't earn anything unless they are the very latest. The newest Tekken arcade game is something like 4 years old, it would never earn its keep.
Kids don't really play the arcade games at the skating rink anymore. Parents usually don't hang out and watch, they drop the kids off and pick them up. I went skating with a few friends some years back in 2003 or 2004 and even then the kids had stopped playing the games. They had 4 machines (the current Tekken at the time, Cruisin' world, an Elvira pin and one more I can't recall). It was a friday night, the place was packed with teens and tweens, we were the only adults there. I kept an eye on the machines the whole time we were there and no one played any of them, not even once.
The most profitable thing he could do is to sell all of them and spend his proceeds on a plush crane, a candy crane and a sticker machine.
It isn't worth trying to deconvert a vector game. It costs much more than an unconverted one costs. There also aren't enough monitors to go around. The sad truth is every vector monitor you find for sale by itself leaves a torched cabinet behind in the seller's backyard (normally a Space Duel). The leftover stock of hoarded monitors in op warehouses and collector basements ran out something like 15 years ago. My buddy and I passed on a converted Tempest with intact sideart for $25 in a recent raid for these very same reasons.