I dont know the answer but wanted to tell you about a horse that used to be on my old yard. It had the strangest looking hind legs. They were very very bowed. She was about 12 yrs old and was used for hacking and it never caused her a problem. I dont know any of her history though, ie what she'd been used for or if she'd ever had any problems previously.
Why is your friend thinking of buying a horse like this?
Oh just realised my question reads in two ways!!
I really meant to say, why do you ask....... Is you friend buying a horse like this? and not ... why is your friend buying a horse like this? Oooops
Mind you I suppose the last one is the most honest. LOL