Violinist here.
Nope, that's not the correct way to hold a bow. The sound would be horrible as part of his hand would be touching the hair-strings of the bow.
It's def a bass as a bass player, but he should be sitting higher up. We have bass stools which are pretty tall but he was sitting at a cello level.
We have French and German bow hold. It looks like author drew him attempting German bow hold but its pretty hard to draw that.
French is what cello, viola, and violin do
I'm sorry if I'm wrong but that was a cello, right? Are you supposed to hold the bow that way?