It's very hard to do a true confo critique without having him stood up correctly for a confo shot. He would need to be standing straight and square, the photo taken directly from the side. A front and rear view, square and straight on, from the hooves up, is a help as well.
If you are going to go through the expense of dealing with previous injuries on this horse, ask the owner for a trial period for 3weeks to see if you can work with this guy and to watch his leg for continued problems. Remember, you don't ride pretty... you want a sound and rideable animal...Be safe!
He is pretty significantly downhill, which will make it hard for him to engage his hind-end. Not saying that it can't be done, but it will go against his basic build and conformation. That said, you don't have upper-level aspirations for him, and any horse can have a go at Training Level stuff! :)
Thank you dantexeventer that is something to really keep in mind when I am working with him and will help me choose work that is more suited to him and avoiding where it is imperative that he is able to really engage his hind. I am really starting to think that the first thing I should do is get going with a dressage trainer to really help me make sure he has his basics all taken care of and find out what other issues he may have as well as how to work with them. I really think that would make everything else come a LOT easier.