“who lived in the tombs.” The Greek text has the noun “dwelling,” as if it was a home, but that is hard to express in English because the man did not build a home in the tombs, he lived there. Changing the noun to a verb, “lived” makes the sentence clear in English. The man lived in the tombs (cp. Luke 8:27).

“in the tombs.” The Greek word “in” (en) can be “in” or, as many versions, “among,” but since the hillsides of that area east of the Sea of Galilee are steep and have many cave-tombs, it is not likely he lived “among” the tombs. That would be akin to living on a hillside with some cave-tombs around. It is much more likely that he lived inside a cave-tomb, but what the state of dead bodies he would be around were, we are not told. They could be rotting, or have turned to dust.