Colour is graded against white background/paper/etc. face down.
Even a K will face up white.
So TBH can't really tell much from this video.
You can ask him to show a video/picture of the diamond facing down on white paper while waiting if you want.
What colour grade is this? Or is that part of the "test"?
The background looks off white so it's difficult to say if that's imparting some effect on the color. If he didn't set any gray balance then you really can't discern any color accuracy.
I'm color sensitive and feel a G is safe. H's tend to show tint IMO though some are closer to a G and fine. You have to find what color grade is appropriate for you.