twin 2 year old boys behavior problem

My cousin has twin 2 year old boys. she has a friend who brings her daughter over and she picked on the boys a lot.Now the boys are being mean to the girl. My cousin called the doctor and said they have a behavior problem.  I don't think they do becausewhen they are around my 2 nieces and nephew they are fine no meaness or aggressiveness what should I tell her? We are a little worried the doctor may be telling her something wrong, without seeing the boys.  Please help.   Thank you

[Kevin Kennedy, Ph.D.]

Dear Rustie,

It's quite common for childhood behavior problems to occur within the home setting and not be in evidence at other sites (e.g., pre-school, daycare, relatives' homes, neighbors). It's reasonable, of course, to let your cousin know that, when the children are in your home, they behave well. Beyond that, it is really a matter for your cousin to pursue with the children's doctor.