Honestly, I love Joey's voice in Anthrax, but seriously he doesn't have the depth and POWER to sing DIO songs. It's just not cutting it. He's perfect for Anthrax but not for DIO songs.
This a terrible recording soundwise (turn your recording volume down to below 3/4 to get rid of the flub), so I don't know how you can even make a judgement. I can tell you one thing. Joey has been a monster for the last few years, sounding unbelievable, nevermind he's 60 something.
Listen to Puddles the Clown doing Holy Diver with Primus. Puddles nails Dio, way better than Joey to be honest even though Joey does a respectable job.