Not gonna be the answer you're looking for, but in our case, yes I get on and cope. Dh would help if I needed it of course, he's had to in the past when I've had my own medical experiences. But day to day, everything in the home and child wise falls to me. He's not intellectually or emotionally inactive to the dc, he'll follow up and want to know about all appointments and meetings, plus of course their day to day, but isn't a physical presence. When he's home he's all about the dc and being with them, not so much cooking or getting up in the night 😅
Unfortunately the set-up is one parent needs to be home and the other has to work. He was the highest earner so it made sense for him to take that role. Due to his work, it does mean he's very physically absent, long hours and usually a few nights away a week.
And yes, I think due to how we've split the roles over the years, if I need help, I would have to verbally ask for it, otherwise he'd be oblivious. But if I did ask, he would do what he could.
If you're new to being a sahp due to a child's needs, make sure you do ask for help, and set time aside for yourself. It's easy to lose yourself when you're caring for a disabled child.