I am the person with ADHD. I am totally incapable. The life skills of planning and doing a task in a certain order that somebody mentioned, I literally cannot do. T
Ordinary people don't realize your brain does this for you semi-automatically. It's executive function, or dysfunction if it doesn't work. The small things I can do, I do very slowly, because my brain is having to think through everything "manually", then forgetting at every moment having to re-remember and re-order, and getting distracted at every moment.
Many life skills that I could do very slowly, I have not been taught because it's too frustrating for anybody to teach me, and they don't think it's worth it as I will just be so slow.
Most people with ADHD have delayed sleep phase disorder, where our circadian rhythm is shifted forward and we fall asleep and wake up extremely late. Our brains are more sensitive to blue light and a lot of us end up nocturnal. Your husband is forcing himself to be normal, quite successfully by the sounds of it, but he will still have extreme brain fog in the mornings (and less extreme but still bad brain fog the rest of the time)
Having an abnormal circadian rhythm affects your sense of time. Most people with ADHD are also time blind. We know logically there is time and order, but we only have the sense of the now and the not-now. The more freedom we have (flexi time etc) the worse we get, because we need routine and deadlines to give us mental structure. Similarly, if you give him 1 or 3 hours to get ready in the morning, he will take ALL of that time, no matter how long it is.
We also cannot predict how long things will take.
Yes, it can be selective, because the high-adrenaline context of work, and getting into trouble for missing deadlines, physically makes the brain think clearer. But this is extremely stressful, and he is completely spent from using all his mental energy at work and needs home to replenish.
Also planning at work is different than planning practical, hands on tasks that he actually has to do. If someone sat him down and told him to plan someone's else's housework and daily chores, he'd probably be able to do a decent job of it, because it's easy to do when you're not in the thick of it.
Doing any kind of thinking or planning or any kind of practical task, is much more stressful for him than for other people. It uses so much more brain power when your brain is inefficient. "Faffing" is not a choice, it is what a slow, disorganized brain looks like to observers.
I am not saying don't leave him, because caring for somebody with impaired executive function is hard and nobody is obligated to be an unpaid carer. It also sounds like your husband doesn't fully appreciate that he has a serious problem, and that it's not you simply nagging him/giving him unreasonable demands. This lack of self-awareness will compound the problem.
But it's hard to see him being described as "pathetic" and the vitriol he is receiving. It hurts because this is exactly how I am seen. ADHD is a disability. He can't help the way he is. By holding down a job, keeping a regular sleep routine, avoiding addictions etc, he's already doing better than many people with ADHD - he is doing infinitely better than me. He's already working at his maximum ability, which is much lower than for non-ADHD people. On the scale of things he's an ADHD success story and deserves credit for his efforts. And yes I'm talking as if he is already diagnosed because he so clearly has it.
He's battling his own inefficient mind. Just remember that you can escape this situation, whereas he can never escape his brain fog, his slow cognitive tempo, or his inability.