Hi @BetUWanna.
Thank you for your update. I can imagine you are feeling dreadful. It's a horrible situation for everyone. I would just say that you did what you did out of love and care. It wasn't a malicious phone call from someone who has barely met the child, who wanted to punish the parent because they didn't like them for whatever reason, for example.
However, yes, your sister's reaction was pretty inevitable. As I pointed out to @FunCrab earlier in the thread, she is likely to be feeling betrayed and paranoid right now. No doubt terrified too. I don't think her reaction of anger is necessarily indicative of guilt. I think any parent would feel the same way at having SS turn up on their doorstep! Even worse for someone who's child couldn't cope with strangers, without a chance to prepare him. But that's on how SS handle things, not you.
As I said to @FunCrab, the danger is that she will isolate herself further - why I was worried/am worried about her suggestion to keep reporting.
I don't know what the right thing to do re telling her is. You know your sister best. Just bear in mind she is likely feeling mistrustful of everyone, which could isolate her further. She's going to be angry with you - yes. It may be easier for her to know though, rather than doubting everyone, with her head going round and round, trying to figure out who it was and exhausting her further. Just something to think about.
I have a family member who works with relevant dept. They say that the client's experience can largely be down to the personality of the SW. Some are great, and genuinely want to help, but unfortunately some are dreadful and sadly vindictive. At best, others can be condescending and judgmental. It would be lovely if they were all coming from a place of compassion, but it doesn't seem to be the case. It's a thankless job, in a system without real resources to properly help, and one which I wouldn't want to ever do, however. I have SW friends in other departments who are understandably jaded and exhausted, and admit they don't always handle difficult conversations well because of this, so something to consider too.
Please don't beat yourself up re Christmas. Even for parents of children with autism, it can often be a case of trial and error. You think you've got all bases covered and then you find a new one! It's just having the humility to learn from it. It's an ever evolving learning process as the child develops and grows. I see people have suggested your sister might be autistic. I have no idea. It could be that the rigidity is just exhaustion, and as others have said, she might have just hoped for a break at Christmas, with more people around to keep an eye on your nephew. She probably should have asked for that help first though. As with all relationships, communication is essential.
The call has been made and the visit has happened, so all you can do is think of ways to best support your sister going forward. She needs to know you love and care for her. I imagine she will be feeling really vulnerable right now.
Might I make one suggestion though? There's a magazine called Parenting Autism, which has some really good, practical articles which you might find helpful. You can download the first one free, which has tips on meltdowns and also explains things from the child's perspective. I think it just helps a bit in understanding the world of an autistic child.
Obviously, no two autistic children are ever the same, in the same way that we can have completely different personalities with NT children. People have a habit of preaching the merits of routine for example, not realising that some children thrive on variety. Some autistic children are really outgoing and sociable, which is often unusual, but struggle in other ways. Why the parent often knows best as they know their child best, so it's important to listen. Humility is really important for engaging with parents of autistic children as they are unfairly judged all the time.
Here's the link for the magazine. Autism Parenting Magazine - everything you need to support your family
I'm going to withdraw from the thread now, as I'm finding myself getting upset and irritated by one or two posters patronising and judgmental comments, who clearly have no experience with autism. Irritated responses won't help anyone and I have to accept some people have no interest in learning or listening, and will always judge, which I can't control. :)
I wish you and your sister, niece, and nephew all the very best. xx