At end of May DH and I are having a party to celebrate our new home. Weather permitting it will be mainly outdoors as we have big garden with outdoor lighting, and a covered patio area. We're thinking BBQ, drinks, fairy lights and lanterns in trees etc and will be inviting friends to bring tents and sleep over if they want to. So not a formal party but relaxing and fun with a 'magical' feel. It's a lovely garden with water features and mature trees, plus a swing, great for kids. Many of our friends have kids, some don't, we're happy for kids to come. We don't mind a bit of noise, boisterous play, tree-climbing etc provided parents keep control. What I don't want is the garden getting trashed or me and DH having to keep an eye on kids if people let them go wild.
Most of our friends' kids are well-behaved. The problem is one of my close friends. She has a 6-yr-old DS who is very loud, rude and obnoxious. He does not have SEN though he's been assessed at school due to behaviour problems and bullying other kids. My friend laughs off his behaviour and says he is 'a livewire'. He's the apple of her eye and she's very indulgent of his behaviour, saying he is 'a bit different'. For the past 4 years, every time we meet up with them he causes some kind of scene. He is always shouting, yelling and screeching indoors though my friend feigns deafness (last week he was repeatedly hitting her over head with a balloon whilst shouting, she just ignored him and carried on her conversation). Last time they came to our house he trampled my flowers, kicked a dent in rabbit hutch, let my rabbits escape then chased them with a stick he'd snapped off tree 
and was generally nasty to the other kids present, pushing and shoving them and spitting on the smaller kids. He also went into our bedroom and bounced on bed. My friend shrugged it off and apart from a few mild attempts to get him to calm down, seemed to think it was ok for him to tear around shrieking for hours, so loudly nobody could enjoy the day. Every time we go to their house he has some kind of meltdown if he doesn't get his own way, and Ive lost count of times he's had tantrums in cafes. Once his dad lost patience and smacked him (for throwing food at lady on next table) and my friend told off her husband in front of everyone and made him apologise to his own son for smacking him! Her husband is very meek and downtrodden.
I can't not invite my friend to pastry and I'm happy for her DD to come, but I know her DS will ruin the party and upset other people's children. AIBU to ask her to leave DS with his grandma for the eve?