Please excuse the essay, I wanted to give context. My 12-year-old niece has recently been diagnosed with autism and ADHD. We get on really well as we have lots of hobbies that bond us. I have a 5-year-old daughter who she gets on with most of time. She also has a 14 year old brother.
The issue is that when she is in crisis, she is unpredictable and becomes very aggressive and violent (mainly to her brother and mum), swears and says the unkindest things to anyone who stands in her path. She has reduced my mum to tears on multiple occasions and calls my dad and my sister’s partner a C**t whenever they try to help diffuse situations. We recently spent a week away with them and spent most days trying to shield my daughter from this. I love my family and my niece very much so we do see them quite often and due to this behaviour, we tend to limit this time to a day at maximum.
My sister had agreed to have my daughter for 3 days over the summer holidays to help with childcare. My issue is that this behaviour is becoming more frequent and I don’t want my daughter to be around it for extended periods. When it gets chaotic there is lots of shouting and screaming and pushing that I worry that my daughter will get caught in the crossfire and get hurt. I also don’t want her to have to witness this let alone the foul language as she does find it traumatic.
I want to arrange alternative childcare. AIBU, how do I broach this with my sister without upsetting her? I know it is hard for her and I don’t want to alienate her or my niece. I still want my daughter to spend time with my niece just not for extended periods.