It sounds like you've had a lot on your plate recently. All places that require and deserve your attention.

Hope your kids are doing okay. A broken thumb sounds inconvenient. Should I ask how it happened? Ouch.

In regard to anger and meltdowns, for those of us who have the control generally associated with being adult, it’s hard to understand that they may not have that capacity. Understanding it from that angle may make it a bit easier to disconnect from it and not waste time engaging. It goes back to ‘didn't cause it, can't control it, can't cure it.’ We often want to help and make things right, and it's hard to back off if you think you have any chance of being effective at solving something.

It's not good for the kids obviously, so a good thing might be to get them out of the line of emotional/verbal fire, and make sure they know they aren't responsible, or the cause of his behavior. You can't fix him, but you can make sure your kids have the boundary and understanding they need.

—>It is sort of weird in a way because it does end up being all about my H, like he will engage with me a ton about his work situation and to talk through his issues but generally passes days or even weeks without asking me anything. Definitely one sided for the time being, and I do wonder how or if we could ever reach some sort of normal or healthy relationship. I guess that remains to be seen. ←–

100% my H too. At times, he recognizes this as well. He will say he can barely keep his own head above water (from a mental standpoint), and that leaves no room for being able to focus on anyone else. Some disorders are rather selfish by nature, which makes it difficult or impossible to have a meaningful relationship. Sometimes the healthy boundary is telling him that I have nothing to give him right now, because I need to keep it for myself.

Dealing with toxic inlaws? Decide on your boundaries, on what you can reasonably do (or want to do), and find a way to make that work for you. This has gotten easier for me as DD has gotten older, become increasingly aware of the problems, and has less interest in being a part of it. When she was younger, she enjoyed going to visit her grandparents, running around their property, and just making a day out of it. I'd just go with the flow and zone out (go to your happy place!) for the day. There came a point though that DD became aware that they were very self involved and not much fun to be around- and also that they weren't very nice to me in particular. As H has become less caring about her and my feelings, I can't justify subjecting either of us to a day of that. I'm not winning any popularity contests with his family at the moment, but am also not taking the hits to my mental health (and am protecting DD’s as well).

Maybe find the balance of what makes sense for you and your kids right now, with a quiet understanding that next year, or the year after, you may choose to do things differently. Do it for your kids if you think that's the way to go, take a lot of walks to get out of the house, have a good book or portable project with you, hide in the bathroom, etc.

As for things here, the more things change, the more they stay the same. It's still the rollercoaster ride where some days it seems like he's doing what he's doing intentionally, and some days it gets scary and seems like he's just not all there. I wonder if I'll ever know the truth of what's happened to him.

Hope that you are doing well. Do your kids have the whole week off? My DD is feeling a little burnt out. She needs some good R&R, and fortunately we didn't have any appointments to schedule for the week off. Yay!