2003 Ford Explorer 4.0L 4x4 runs out of gas.

My son had his 2003 explorer towed over to the house because it died on him going over an overpass, fortunately he was headed in the downward direction. I tell him to get in and crank it over. No go. I get behind the wheel, turn the key to the on position and the needle is on "E". You're out of gas, I said! His response? The light didn't come on, nor did it begin to ding. Tom hit all the points. Don't drive past half a tank. For obvious and mechanical reasons. And change the fuel filter on a weekend, they're not that expensive.