Would Love to Hear Ken's Thoughts on Steve Tyler's Performance of "Walk This Way" with 2Cellos

cosmos2015

I would be very interested to hear Ken's thoughts on this performance. Sounds to me like Steve's voice is getting a bit strained now, but I'm impressed that he can still do it. How do you pull it off safely and correctly?
https://www.facebook.com/654411161636424/posts/905589743185230/