I like Onyx's idea there. Otherwise......... I would have to say this would fall into the category of a white lie. You aren't lying for self preservation, more to protect her feelings. If she isn't ready to acknowledge the issues her kids are having... there isn't a lot you can do. And most likely, any discussion (however gentle and lovingly worded) would leave her with a bitter taste in her mouth. You can't really win.

You know her better than I do, obviously. Maybe you could use a combination? eg- tell her it was a school only party, as well as the fact your DS has verbalised being anxious in her kids company. Explain that you don't want her kids to feel left out, or for her to feel offended, but you really must put your DS's needs first. Given that you're taking to a psych, she should be understanding if you fib about the psychs reccomendations re- his anxiety.

I don't like to lie either, but sometimes it's better than rocking the boat. Your friend sounds like she's had a rough time, so anything you say about her kids behaviour will feel like an attack to her. (presumably)

HTH. FWIW, I think you're a great friend to be so carefully considering how to preserve her feelings. If it were me, I would accept it if you 'gave it to me straight', just on the merits of what a caring person you seem to be. I would understand you weren't trying to upset me or hurt my feelings. But that's me. If she knows you well, I think you'll be fine. She should understand that you're trying to do right by everyone involved, and people tend to look at intention, rather than actions... ITMS. Good luck!