A bit of background first
I have never really gotten along with my sister. When we were kids she was very competitive and my mum's favourite and she used to use this to make sure that me and my brother were always in trouble for things.
After we married and had DCs we only really saw each other for Christmas and birthdays.
The I left my exh and we started talking a bit more and she took more of an interest in my life. However she can still be competitive especially around the DCs. Anything my DCs do hers did earlier/faster/better. Also My sister home schools and she always feels the need to tell me how much better it is when compared to state schools , so I tend to avoid bringing up stuff my DCs do.
So my sister contacted us and arranged for us all to go on a family holiday this weekend. So me and my 4 DCs (12,8,6 and 1), my sister and her husband and their 2 DCs (14,10) and my brother.
Each family has their own caravan and the plan is to split the days so we spend sometime all together and that the adults all get a break away from the DCs.
So we arrived yesterday morning, and yesterday afternoon/evening I looked after all the DCs and my sister and her husband had some alone time. I took them out and fed them and everything went well.
This afternoon was my turn without the DCs so I dropped my DCs off with my sister and went out. My sister called me earlier saying she wanted me to pick up my DCs now because they weren't behaving.
So I arrived to pick them up and she pretty much threw them at me and DD2 was crying. My sister also looked very angry and stressed. I asked what had happened and my sister said they wouldn't join in and DS1 in particular had been very rude and she was very disappointed in them. I made the DCs apologise and took them back to our caravan.
So I asked DS1 (12) first what happened. He said that my sister wanted them to play a quiz game. She had piles of questions already chosen and she split them into teams her DCs against mine. Then she made DS1 and her 14 year old go against each other but when DS1 started winning she made them stop halfway through the questions.
Then it was her 10 year old against my DDs. DS1 said the questions were really hard and were all in a subject that her 10 year old has a special interest in. It's also a topic that they don't really teach in schools. My DDs lost and this time they finished their pile of questions which meant that overall my sister's DCs team had the most points. My sister then brought out prizes for the winners and nothing for my DCs. Then she said they would play the game again with the same teams.
DD2 (6) asked if they could play something else and my sister said no. DS1 asked if they could mix the team's and my sister said no. DS1 said that this wasn't fair and his team was never going to win. My sister said it was my DDs fault for not trying hard enough which upset them because they had tried their best.
My sister said that really it was my fault then because I sent them to a school which meant their best wasn't good enough. DD2 started crying and then my sister shouted at her for spoiling the day. DS1 said that my sister spoilt the day by rigging the game so her DCs would win. My sister then shouted at him too and then she called me to come and get them. Then she told her DCs to go in the bedroom away from mine so they didn't learn how not to behave.
I then talked to my DDs separately and they have told me pretty much the same story. I text my sister and asked her what happened and she replied that they wouldn't play nicely and were bad losers and I needed to have a serious think about their behaviour because her DCs never act like that because they don't pick up bad habits in school and work hard at learning.
So would I be unreasonable to text her and suggest that the families do their own thing for a bit tomorrow to give everyone some space. Admittedly I am pretty sure the DCs are telling the truth DS1 has ASD and is very honest. Plus the DDs story matched up as well. But I'm not sure if I should push my sister to talk about it or just let it go.