New friend and sibling

[wendmatt]

DD just made a new friend in her class. He is a sweet quiet boy and we invited him over as he lives in the neighborhood. When we went to get him his sister (5yo, DD and friend are almost 8) wanted to come. His mom kind of hesitated and looked at me and then said maybe another time. So, today we call and invite him over again and the mom says that sister gets upset if she is not invited. I didn't invite the sister and DD ended up going over there (DD has never even met the sister apart from seeing her when friend came over).
Am I being mean that I don't want the little sister to come. DD and friend play well and are quiet and I can get alot of work done. Adding a little girl would change the dynamics, plus she is not dd's friend the boy is.
I feel like saying, well that's a shame that she's upset, but I'm sure she'll have her own playdates, she can't go everywhere with her brother.
Am I being unreasonable? Feels like I'd be babysitting not having a playdate for dd. What should I say if she asks if sister can come over as well?

[hillview]

ODD. I think you are very reasonable and I don't get that at all. Sorry -- bummer for you DC!
/hillary

[Ceepa]

I understand the mom doesn't want the stress of sister's meltdown but that is not in any way your problem to handle. Also your DD is having fun with a new friend. It's not fair to her to have the 5yo there, too, when she doesn't even know her.

[wendmatt]

Thanks, I kind of needed a bit of reassurance that I wasn't being unreasonable as I only have 1 and don't have to deal with sibling stuff like that. I did however have 3 sisters and if one got invited to a friend, the other/s did not expect to go.

[s7714]

I wouldn't invite the sibling. It's not your problem.

I feel sorry for the boy though if his mother keeps up the "you can only go if your sister can" thing. It won't be very long before that boy seriously starts resenting his sister!