That's a terribly unflattering photo! And it's misleading.
Here's a short video interview with him in November. He looks and sounds in great shape, is writing songs for a new album, and is energized by his tour schedule. He says it's not hard work because it's fun.
https://www.youtube.com/watch?v=NlG3A3X4HgA
For a guy who's had the life and health problems of Gordon Lightfoot, it is a miracle he even made it into his 80s. And to still be so excited about making new music, recording and performing... Wow! Amazing!! Hope to catch one of his tour dates.