He has become disabled. He has made sure he keeps his job. Due to disturbed sleep - caused by said disability - he sometimes works until 8pm to make sure he keeps his job presumably and because he can still contribute to the family by providing income. Since walking hurts, I'm assuming you aren't expecting him to put a wash on or take his children for a kick about in the park....so he is doing what he can.
You are not a single parent. Parenting alone and being a single parent are very different, believe me. Single parents are not 2 income households - or households where one person brings in more economically and the other contributes more to domestic chores. Clue is in the name.
As someone who is a single parent, works full time and is disabled, I'd say you need to catch yourself on.
I'm afraid as others have said, while his disability impacts you, it doesn't impact you as much as it impacts him.
Mercifully I have medication which keeps my disability mostly under control. But being in constant pain, walking hurting, not being able to sleep because of pain - I know what that is like. And I worked too.
It's harder than parenting a couple of kids as a fully healthy person, believe me.
I get that it's hard for you, and you are upset. But you need to talk to a therapist - and try to come to a compromise and also please please try to find empathy for him. Until you have been in relentless pain for weeks and months combined with the fear that you will never get better, you have no idea what it is like. And it's lonely and hard. And you fear losing everyone and everything because of becoming a burden. Please please do t make him feel a burden as he sits in the living room working and making money for the family. He could have taken to his bed depressed. I never did that either but believe me, it's not easy to choose to fight day on day out, forever.
Also, he is working till 8pm - that's not that unusual anyway. He's not making loud phone calls at 2:30am waking up the whole house.
YABVU