Most everyone on this site will agree that it's best to house your ball pythons seperately.
If your dad's friend who is a breeder is keeping his that way, then I'd suggest you ask him for advice on how he keeps his together. While you do that, ask him how often his snakes eat(not how often he tries to feed them, but how often they actually eat), how many regurges he experiances, what the weight gain is on the snakes kept together, and what he does when one gets a resp infection, or other medical issue.
If you have some reason for trying to keep two snakes together, then you can try to do that. But it's preferred by MOST people who keep/raise/breed ball pythons to keep them 1 to a enclosure, for many many good reasons. I haven't yet heard a GOOD reason for keeping more than one snake to a enclosure.
Just my own advice, keep them seperate, and preferably smaller enclosures for smaller ball pythons.