The ligament tear is really serious on top of the rest of the issues. I would plan on 24/7 stall rest for 3 months and then QUIET turn out for a year. Add the special shoe and compensatory trims with a top farrier throughout. See where the horse is at that point (15 months). IF you have the time and money.
If no better, well it is not like you did not try or give the horse a chance to heal and learn how to compensate.
I am sorry.
There is something about the outside of a horse that is good for the inside of a man. ~Winston Churchill
) Dinosaur Horse Trainer