My brother is the autistic one
Yes, please identify the people you are talking about. It is not clear. Is it your brother that is autistic?
Wait, are these people saying your brother molested HIS nephew or the nephew of the owner of the trailer park? If they're saying it was his own nephew and since you said you do not have kids, if the police get involved and realize you do not have children, you can say you want to file a report based on "slander." Which is basically: spreading incriminating lies of an individual.