I personally find that if you have pig that you want to become friendlier with people the last thing you want to do get another pig. If he is not neutered yet and get a female to breed with him he is going to bond with the other pig and want nothing to do with you. Be fore you breed pot bellies look into how much demand there is in your area for pet pigs, because you could end up with 12 piglets. If no one wants them you will be stuck with numerous adult pigs and spaying and neutering can be pricey. His behavior will also become more aggressive because of his out of control hormones. You may just kill your chances of having a friendly lovable pet pig. My pig Pickles hates other pigs with a passion and someone had given me another spayed female a few months ago and Pickles was absolutely miserable with another pig around so I had to give the other pig away! My grandmas pig when I was a kid was an unneutered 400lb male commercial hog that lived in the front sun room of the farmhouse. He was such a friendly pig until the neighbor got pigs and he picked up the scent of female pigs, made his way over to the other pigs and bred with a few of them. After that got really aggressive so she had to neuter him but he never was quite as friendly as before, and ended up having to live in the barn.
I would just neuter your pig and then keep trying to feed him treats by hand and just give him time. He should eventually come around but you may never end up with a really friendly cuddly pig.