I’ve been watching this conversation since my previous post and reading your posts @Pumpkinlatte1235 and I found myself wondering about a couple of things compared to my own experience. They might not be relevant at all and you might have explored them already so feel free to ignore me completely but,
Do you think there’s any chance that your oldest is actually really worried about his brother and is feeling excluded and helpless around the care of his brother in your home in a way that’s making him act like this? You say that he’s caring towards him and that he helps him when they’re at their dad’s but you also say that you are the only person who can Co-regulate with your youngest and that DS1 is not involved in this when they’re with you.
lt’s not DS1s responsibility to care for his brother BUT if he’s seen a massive deterioration in his brother over the last year, and is witnessing his brother coming to harm, or possibly worse, being kept away from his brother when he’s like that and not really knowing what’s happening, then that is going to be upsetting and unsettling for DS1.
If DS1 is able to support his brother when they’re at their dad’s, and if DS2 is able to mask more at his dad’s, then it’s likely that your eldest spends all his time running catalogue on his brother when they’re there and adapting things he has any control over, and he may well have spotted triggers, or early signs of overwhelm, that you haven’t and he might be looking at how you are dealing with your youngest and feeling that there are things you could do differently that would improve the situation for all of you which will only increase his frustration with you.
I’ve asked my kids about each other when I’ve been struggling to workout the cause of an issue and often they’ve helped me find some ways forward. Their views and thoughts are valued, they feel good because they helped their sibling, and life improves for everyone because I have a better handle on an issue. The responsibility to ‘fix’ things remains mine but my kids know that I’m always open to their observations.
Maybe a conversation like
”DS1 I know you really care for your brother and that you do a lot to try and support him when I’m not around so I was wondering if you’d noticed any signs I might be missing of when he’s starting to struggle? I’d like to get better at helping DS2 to learn how to prevent his meltdowns because they’re distressing for all of us and can really ruin our plans but I don’t think I’m doing a very good job of noticing early warning signs right now so would love to know if you’re seeing things I’m not.”
He might refuse to talk, he might get angry and unload all his thoughts on you in a way that you might feel is rude, but he probably has lots of useful things to say if he can get them out and you can really hear them, and feeling involved in the solution rather than excluded from the problem might be a powerful thing for him.
My other thought on this is, have you ever had a family meeting about this? Have you sat together over snacks, all three of you, and discussed the situation. Have you stated your expectations to both boys that your job is to help them grow up into responsible adults, that you expect them both to be good people, to care for those around them and to have all the opportunities in the world. Have you told them both that while support will be provided for all their needs, and that might look different for each of them at different times, you love them both dearly and you care about them both, but you expect them both to show you and each other the same kind of care and respect?
I ask this because sometimes we forget to say these things out loud and just assume our kids know them and often, in situations such as these, they get lost behind the necessary caring and the expectations around behaviour and support for others begin to sit on only one child, the one not being ‘cared’ for which feels like further unfairness to them.
The first time I said to one of my kids who was being a pain on a day out “I’m pretty experienced now at spotting the difference between autism and misbehaviour and we both know which one this is” was a revelation to me and to my kids because all three of them heard it and took a mental step back. It put a line in the sand that while I would care for their needs and fight for their right to accommodations and support I was not going to accept misbehaviour from any of them. Your older son needs to know that outside of the uncontrolled behaviour within a meltdown your behaviour expectations are the same for both of them AND that you are working with DS2 to reduce uncontrolled meltdowns in the first place.
like I said above please feel free to ignore everything I’ve written here if you don’t think it’s relevant to your situation.