The "Web Filter Lite" on Untangle would accomplish what he's looking for, but he'd have to either purchase an untangle device (cheapest one is $995) or convert a computer to an Untangle server (the software is free) and put it behind a switch or router. If he had an old computer laying around he didn't need anymore it could be a possibility.
I don't know the poster's technical expertise level so I don't know if this would be easy for them or above their head.
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