Child Behavior: Creating a Monster

I don't like what my brother and his girlfriend are doing with their son. Their child is not abused, neglected or otherwise mistreated, but he is turning into a brat. His parents are completely crazy. They have very strict rules about everything. They feed him a vegetarian, dairy-free diet. He never plays with other kids except for my two boys, and then it's only about once or twice a month. His mother has been home with him for his whole life, and my brother is extremely active in raising him. But their efforts are backfiring. Everything that they preach as parents is going right out the window! They preach tolerance and respect. Their child has no respect. My son is exactly six months older and when the kids were younger, they constantly yelled at him for hurting their "baby." Well, their "baby" soon outgrew my son. So now their kid is bigger than both of my sons and he plays the victim in every situation.

His mother is the kind of woman who literally spends every minute of the day following her son around and playing with him. He believes that he should always be happy and that someone else is responsible for making that happen. My brother has the best intentions as a parent, but something is going terribly wrong in that house. This child's mother truly believes she can shelter her son from anything "bad" and she is ruining this bright little boy in the process. He has no idea how to interact with other kids. My 14-month old son has learned to just give him what he wants so he won't scream and cry.

It is ruining my relationship with my nephew and my brother, and I have no idea how to talk to my brother about it. He will get defensive and take it personally. But if the situation gets much worse I simply don't want to see them. A relaxing day at grandma's is no longer that at all. It is filled with screaming, crying, kicking and hitting. One memorable day their son bit my older son on the cheek and kicked my younger son. He's out of control and his parents are oblivious to the fact that they have created a little monster. They feed into his behavior by playing it off with excuses like "he's tired," "he missed his nap today" or "he was up late last night." I don't buy their excuses at all.

Any advice on how to approach my brother would be great! They need help, but I don't know how to give it to them.