To be honest he is an awfull mover, I don't think he is sound and I highly doubt he will pass a vet check. He does look like a nice quiet horse but I think you would have a lot of problems with his health. Even trying to bump him up would not make him a better mover because he is unsound. I hate to be harsh but if you are looking keep looking. That is my honest western pleasure eductated opinion.
It struck me right from the time she trotted him for showmanship. He is not reaching like he should be and his knee action makes him look very sore. At the trot under saddle again he was not reaching or moving smoothly. Also when you see a shot of him coming down the rail his rythym looks very off. His lope is not true at all. It is a very scrambly 4-beat gait. At the lope he looks sore in both his front end and back end. It looks painful for him to move. A different rider will not make this horse look more sound either. There is nothing smooth or free looking about the way he goes. IF IT CAN EVEN BE DONE you will have a ton of maintenance cost to get and keep this horse sound. Your $2500 horse will quickly cost you much more. In todays market I think you can find a much better and more sound horse for $2500.