This is so bad. In fact I am disappointed with the school. Why are they allowing this to happen. Bullying because of the parents. I am really saddened with this information. I am a part time counsellor and I have heard such cases. In as much as we discourage this. This behavior still remains. Mainly due to the parents of the bully. If you further investigate you will find that the other parents are the ones responsible. Like a parent telling the child not to play with your nephew. Just because his parents are gay. Maybe they feel the son will also be gay. And they are preventing their children from being gay too. The best thing is to speak to their children. Explain to them about everything. Not telling them to isolate your nephew. I can call that bad parenting. I think your brother should move his kid to another school that care for children from LGBT family.