This video has been debunked as FAKE by the Fact Checkers. This is the only video I could find (please archieve).
Other videos with the same title show a different video without this family and without the hand-off.
I think it looks real: https://www.facebook.com/FOX19Cincinnati/videos/866047397623585/
Video Length 26:40
Biden giving boy vial 12:37
Boy pocketing vial 13:03
How can we tell it is a vial of blood? I zoomed in, and it looks like a mass of black threads, or elastic.
Biden is also holding a black mask. Look at the boy looking at his own hand holding it.
Look at the shape of his hand while holding it, like he's holding a cylinder.