Yes. I’d say the timing issues are more related to breathing issues, as if he doesn’t have enough breath in order to keep up with song, thus he has to stop and breathe, becoming out of time. Jon always had a great voice, but never a great singing technique. As long as he got the pipes, his technical flaws were “hidden”. Now that he doesn’t have them anymore, the issues are all out in the open, for example the breathing issue.

As for the tuning issues, every note you reach and/or hold requires some “effort” on your vocal chords, regardless if you’re using your lower, middle of upper range. Vocal chords are like muscles, the more damaged they are, the harder it is to apply any effort on them. That’s why he can’t reach or hold the right notes anymore. His vocal chords are too damaged to allow him to.