I think that if she's a good friend, you should say, "You seem really stressed about the kids." and go from there. I think that if the kids' behavior is making you rethink the outings, then you need to try to say something to her. Maybe you will have to do more without the kids to maintain the friendship. Or maybe she'll change and things will be better with the kids.
The other thing I wonder is, what's different, if they are worse than usual? Is it their ages? Did their parents take new jobs? Did they move? Etc.
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I think that if she's a good friend, you should say, "You seem really stressed about the kids." and go from there. I think that if the kids' behavior is making you rethink the outings, then you need to try to say something to her. Maybe you will have to do more without the kids to maintain the friendship. Or maybe she'll change and things will be better with the kids.
The other thing I wonder is, what's different, if they are worse than usual? Is it their ages? Did their parents take new jobs? Did they move? Etc.