OP- big hug. This sounds very tough on you.
One suggestion (courtesy of my therapist- completely different problem but I think a solution which might work for you)-- segregate (either mentally, or go the ATM and put actual dollar bills in an envelope to stash away- her suggestion was “put it with the cleaning supplies, nobody in the house EVER goes there” which is both true and hilarious) an amount of money which isn’t life alteringly huge, isn’t $3, but represents to you “what is my mental health worth today”. That’s your mental health fund.
Every time one of these incredibly stressful AND stupid AND crazy issues come up- with your spouse, your D, or anyone in your life you can’t just write off- take the cash out of your mental health fund and make that problem go away. No, this is not a permanent solution to your D’s independence or the lack thereof, or a solution to you feeling torn in many directions, or your H not seeing the issues the same way you are. You’ll deal with those things in due course.
But for now- don’t allow yourself to get rattled (especially after a long drive, watching someone you care about die, you not being at the top of your game emotionally) over stupid stuff which can be fixed with cash from your mental health fund.
What’s it for? The pizza delivery, even after you and your H decide you are going to eat less takeout this year for nutritional and health and financial reasons. The four pack of toilet paper from the local grocery store, even though you know you should have made time on Sunday to go to the big box store and buy a 36 pack so the rolls cost half as much but you had too much else going on. Replacing the sweater that shrunk in the wash because even though the tag says Dry Clean Only you didn’t have time to go to the dry cleaners because you had 40 other errands to run after work and they were in different directions. And you loved that sweater and are furious and upset that you ruined it by being in a hurry.
For now- during this stressful and fragile time in your life- you are going to use your mental health fund to make these problems go away, and you aren’t going to even think about the money once it’s spent, because that’s what it’s for. YOUR mental health.
It strikes me that your life right now is just like the 80/20 rule- 80% of the stressors in your life are due to stupid stuff which can be fixed with an infusion of cash. 20% of the stressors are huge and complicated and will take months of effort and help and therapy, and really- nobody can fix those except for the principals involved.
But take that humungous stack of problems that are causing so much grief (really- did you need to be scolded by your husband after spending the day on such a tragic errand?) and make them go away. For now. To be dealt with later.
Hugs to you. I think most of us have been there at one point or another, and you need to put on your own oxygen mask right now before you can help anyone else.

