Im saying this with as much respect as possible: I personally think that your friend couldnt see the signs of a problem if it slapped him over the head. Snakes that cohabitate together compete. For warmth, space, everything. From the sound of it the balls are very stressed and they eat but that doesn't mean he's doing things the right way. Just because the animals have lived together for 10 years definitely doesnt mean anything to me. In my honest opinion he's not doing things Right. If he cared about each snake he'd have completely separate enclosures for each one so they don't have to compete for it. Ie laying all over each other. Snakes don't cuddle, and the only reason two of the same species animal come together is to breed. Some species have to be kept together bc their husbandry and high level of care requires that. But that really is for hot snakes I believe.

You can buy a snake from a reputable breeder and still have an issue. Somethings are asymtomatic until stressed or Inadequate husbandry. Housing more than one together you aren't going to know what did the runny poop. Or who regurged etc.

Anyways I think they are all gorgeous jcp, ij, rtbs all of them. But im going to urge you that even if you get another ball and especially if you get a different species to house them separately. Even if they have the same requirements which actually if you do enough research you'll find that none of them have the exact same requirements as your ball. Simply because balls get stressed in large enclosures, and with a cage mate.