What was wrong with Sly at the Grammys?

Watching the Sly and the family Stone review at the grammys, I was hoping to see Sly, which he finally showed. Of course the white mohawk was a bit shocking, but getting over that, he didn’t really seem there.

His hand was bandaged up, and it appeared that his mike wasn’t working at first, but he switched to another mike and got off a line. Then he just walked off stage.

It appeared that it wasn’t orginially planned, as at least there appeared to be a plastic tube for some kind of voice box (like the guitarist’s use?)…

I know he used to (still does?) have a pretty bad coke habit, but he really seemed out of it.

Any guesses?