I enjoyed both links, his song and his interview from the OP.

His warming up approach is very much how I have approached the guitar all my life and as I have gotten older. Physically it takes time to warm up and as a person gets older, it takes more time, both with fingers and vocally. And also, yes, the fingers tend to hurt and ache from the effects of osteoarthritis. But somehow, most of the time, you figure out a way to keep going.

Very interesting stuff!

- Glenn