As already said, the OP mentioned nothing about a vulnerable person who isn't capable of defending themselves - for all we know they might not even consider the treatment as serious as those dishing it out. Again i've known people like this - they come from the kind of environments where mocking unfriendly behaviour was common and just the way their family members responded to each other.

I think we need more information to be honest - we're trying to work out this situation from one side of story, what you're saying could be just as correct as what i've suggested.