He might indeed get bitten. That is the terrier part of Boston Terrier, as my vet says. They are feisty and have a tendency to snap (with their mouths, I mean). We have always had Bostons in my family, and we have had some biters. The good news is that it's usually brief, like a snap, rather than a tearing bite (I speak from firsthand experience-- often there's no wound, and if there is, it's usually a small bruise, like from a pinch, rather than a rip.) Also, it seems to faze other dogs less than it does humans. Your Boston is asserting his dominance, which is normal. Hopefully the hierarchy will be set to the Boston's satisfaction and he will behave like a gentleman (as I always told Banjo to do). Then, having that dominance in place can actually be beneficial in training and raising the puppy (I've heard) since the Boston would serve as a role model that puppy will watch for cues. Do keep an eye on the dogs together until you can trust the Boston to be gentle. Though Bostons are very smart and usually know how to get their point across without crossing the line, puppies can be stressful on older dogs, and that's why he may snap. Dogs, being pack animals, socialize themselves like a family, and though brothers and sisters don't get along sometimes, they can really be helpful at others. I wish you canine peace in your house and that they'll be cleaning each other's faces (the cutest symbol of animal sibling love) very soon.