It is extremely difficult. We had some very good friends, but their Twin Daughters were down right mean. Everyone calls them the "Evil Twins".. Even kids that are their "friends" are afraid of being on their bad sides.
The parents were so kind, funny etc. But their daughters would say and do such hateful things. We were (neighbors) even able to prove it many times, but the parents seem to just not understand, They finally moved far enough away to be close, but their daughters in a different elementary school.
We saw them maybe 2 or 3 times a year.. and that was enough to remind us, how awful the girls were.
One of our close neighbors was best friends with the twins mom, I asked her, "are the girls different with your children?" She said "no they are just as bad." I asked her, "have you spoken with the M and R about it".. she said "oh yes, I tell them all of the time, but they just smile."
This neighbor said she just kept as close an eye on these girls as possible and would speak up in front of all of them when she saw or heard the girls being mean or trying to get other kids to do dangerous things.
It became more and more clear to most of us, these parents, were not as nice as we thought they were.. Passive aggressive, extremely competitive and secret bullies. They are such a good looking family, very talented intelligent, but man they like some sort of gang/clan.
They taught their children well.