Sometimes, a submission don't has to be too long, especially when it delivers it's message in a short, but fitting way. This one is on point. I don't know how you dad reacted to this but I'm rather sure he was both happy & proud.
I don't think the animation needs more content, just some more sound (music score or voice-over) and I it would rate it even higher. But it's good the way it is already, imho.