If the video is of him at 8 months, then he looks very immature.
Longing the thing for hours at a time is seriously bad, and could seriously affect the development of his legs unless it is stopped immediately.
I think the best advice if you want to adopt the guy, is to put him in a large pasture with a couple docile mares and let him "detox" from humans for a month or so. I think if you take him home and try to "fix" his trainer problems right away, he will become very frustrated and unhappy.
He needs some good feed and some good hay and some good mares to teach him some manners. Once my filly starts acting onery when I'm working with her, I know it's time for some baby detox. I put her in the pasture for several weeks and don't touch her, just to get the frustrations and bad attitude out of her mind. When I bring her back in, she is much more willing and "refreshed".