I think to challenge this you need to understand executive dysfunction and particularly in ADHD what role dopamine plays in this and how the brain processes information differently.
I don't know if you've heard this analogy before but if you're stood over a fire, and someone tells you to put your hand in this fire, you're able bodied you can physically get up and put your hand in this fire, you still wouldn't put your hand into the fire because your brain is telling you it is dangerous, and it is painful.
To an ADHD brain, a task that doesn't spike dopamine is interpreted by the brain as pain or danger. Of course they don't feel pain, but the brain says this task is so boring, it is painful and so I'm not going to let you put your hand in this fire.
Are your ADHDers medicated? Because the medication should help with dopamine boosting.
The ADHD internal reward system works on novelty, urgency, and interest. That means for an outsider you might see them do a task whileever it is a new task for a while, then stop and you think oh my God I'm having to pick up the slack again, or you might find that they do it again if you shout and raise your voice or lose your shit because that is urgency, or you might find the will only fulfil a task if it pertains to a hobby, ie. I need to put this basket of things away because I need the screwdriver at the bottom of this basket to do the thing I want to do.
So then we get onto executive dysfunction.
Executive dysfunction is the dysfunction of our executive brain functions, and it affects our ability to keep time, so we might not be able to do things in a timely manner because we experience time blindness, it affects our ability to start tasks, even if it's something you really want to do but even more so if it isn't rewarding, it affects our ability to switch tasks, so if you need to put the car in the garage but before you can put the car in the garage you need to move the boxes and before you move the boxes you've got to sort out the little bedroom so there's no point in doing anything at all because it's all too much and it's overwhelming, and it affects our ability to complete tasks.
With autism especially, it's hard to be motivated by an internal reward system, there's often no sense of satisfaction for getting things done, especially if it deviates from plans, routines or schedules and instead it makes us anxious, which means we can't regulate ourselves and therefore we lose executive function.
Going back to ADHD, people with ADHD have poor object permanence. Ie, you put your GCSE revision things down with the intention of using them later, someone comes along and tidies up because they need that space, and suddenly GCSE revision does not exist anymore. It's original placement was a visual reminder that it needed to be done, and now it's gone it will not get done because there are tasks that need to be started, switched and completed like finding where it went before you can start the task of revision.
Neurotypical systems of putting things back where they came from so you know where they are don't work for neurodivergent people and in a house with multiple neurodivergents and competing needs it will understandably be chaotic.
This is where shit baskets come in.
Everyone gets 2 stair baskets. 1 stair basket goes on the stairs, the other is empty and left away for rotation. They can put what they want in that stair basket because eventually they'll need it.
When that one becomes full, you put that in their room, and you swap it for the empty one. If they don't empty it, you do, you just dump it on their desk. Their rooms are their problems if they want to live in a shit hole, let them. That solves the clutter problem. If you want to you can put a larger shit basket in each room for dumping the stair shit baskets into.
Then next you need to work out systems that will help each person start tasks. It has to have instant gratification to be impactful and it probably won't be the same for everybody. Even as an adult I have to admit I found it hard that I never learnt how to start some tasks. Not knowing where to start was so overwhelming to my nervous system that I needed to seek dopamine, but then would not be able to switch tasks. This is especially hard if you are both autistic and have ADHD. I'm talking so overwhelmed by responsibilities that you can't even take a shower level of inability to switch tasks.
Lastly you need to find a way to pick your battles and live with what you can't change.
These are genuine disabilities. It's not a lack of willpower or laziness. There can be learned helplessness, which is why it's important each person understands why they are the way they are and tries to find systems that work for them, but it's not just a case of taking the neurotypical folk for granted. It genuinely impacts on our abilities to complete daily living tasks.
See if any of you are entitled to DLA or PIP, and use that to fund a cleaner or hire a laundry service or anything that can make your life a bit easier.