Tie Back surgery--any experience?

[not again]

A friend of mine is looking at an ottb that has had tie back surgery twice. The horse is very attractive, but still seems to struggle with breathing. He aspirates his food, and according to my friend, grass comes out of his nose when he is grazing. He has had a couple of bouts of pneumonia.
Is he a lost cause? Should she get the surgery redone?
She is hoping to rehab him into a nice low level all-round guy.