He obviously is going to blow the record away, I can't see how he wouldn't. 49.7 was on a regular bike, with tech from 20 years ago (I think back in the 90s someone did a 55ish already on a tri bike).
Considering the pros TT at over 50kmh OUTSIDE, I can't see why anyone would expect him not to beat it.
I would guess 56kmh, just because.
What bike is that? A speedconcept with track drops? I like it