John, I would agree,, seems like he stayed with/in the bike for some number of feet during the slide.
His left foot may have hung on the peg in the fairing,,, that seems to make sense of the extensive left foot damage. If he was clear of the bike a basic slide like that should not have wore thru his boot..
Just my thoughts...
Glad Bill is well and on the mend.
Hope everyone has a safe and Happy Thanksgiving
Charles