Could be just the angle, but he looks very fine boned with tiny feet for his rather large body. Pastern length and angle looks ok. None of these photos are ideal for an eval, but he appears to have a fairly upright shoulder and I am not a fan of how his neck ties in to his withers. Back is a decent length and seems like he has an ok loin. Hindquarters look overall somewhat weak and poorly developed.
And although the ad says UTD on worming, he looks wormy too me, or maybe just a hay belly? I guess if he is close to you he might be worth a look, but I don't find his conformation to be ideal for jumping, except perhaps at low levels. His temperament doesn't sound too good either, but if your friend is looking for a project and just a low level horse I guess he is worth a look if she enjoys working with difficult horses.
I think this horse looks more promising and is overall more balanced and sound looking. And although not broke she sounds to have a better temperament. --> 2002 AQHA sorrel mare - $350
The paint has a potbelly, too fine legs, small feet, an ewe-neck and I am not too sure about his hindquarters, although I can't put my finger on it, maybe it's the shape (they seem to have decent muscling) or the way the tie into the loin. Not that the potbelly couldn't be fixed with conditioning, but of greater concern with respect to jumping are the very fine legs, small feet and the long-ish, weak loin. Add that to his difficult temperament... Not incredibly promising.
I agree wholeheartedly with Tryst that this chestnut mare is a better looking horse and more promising than the paint. This mare has a shorter, stronger loin, stronger, more rounded-out hindquarters, nice shoulder, elegant neck that's neither too high nor too low and ties in better to the shoulder/withers, stronger-looking legs with better-proportioned feet. She is also already nice and trim so you won't have to burn weight off her. The only thing I can see "wrong" with her is that her coat needs some elbow grease. :) But as far as jumping, I especially love her hindquarters and loin, I think she could do really well. Yes you would have to finish her training, but she seems to have a good, willing temperament according to the ad (but who knows...). I don't know anything about QH bloodlines (her parents are listed in the ad), but she seems to have good genes from looking at her!