There is a physical limit of sleep deprivation that someone can sustain before it significantly impacts their ability to function cognitively, so to ensure safety, as well as physiologically, it can cause anxiety, depression, panic, hallucinations as well as have an impact on our physical health.
When parents of SEN children say their kids aren't sleeping they don't mean their kids stay up past 11 sometimes or occasionally like to get up as the rooster crows.
We mean our kids are up past 11 most nights, then up through the night for hours at a time, and then are waking up ready to start their daily routines at rituals at a ridiculously early time and when they are awake they need their bodily needs to be met. They need feeding they need to be given a drink they need help toileting or changing from soiling, they need to be supervised because they cannot understand risk and they're elopers, sometimes they're just so upset and we don't know what they need they might need comfort they might need space they might just be bored, they might be trying to communicate something and struggling, and they can display self injurious behaviours, some of our autistic children also have pica and will try and eat things that aren't edible at all and are dangerous and need redirection. We're also mindful of everyone else needing sleep so we do whatever we can to make sure our children are quiet and happy. It's beyond exhausting.
Someone said it earlier in the thread but if your children are at school then you are basically working 16-18 hours a day 7 days a week and the only break you get is when your kids are at school for 6-8 hours if they're even able to access school for that duration of time. Many don't. Many are on part time schedules despite being entitled to a full time education, or have been suspended or excluded as there's no suitable alternate provision.
It's not the same as having a neurotypical non disabled child/ren. You might have to stay up late and put them to bed and get them a drink or a snack or read a story and listen to a thousand excuses about why they want to get out of bed.
It's like the newborn phase where you're so exhausted that you catch yourself nodding off because you're at your absolute limit except it never stopped when the newborn stage ended and it feels like torture. I'd say groundhog day but every day your child gets bigger and stronger and can do more harm to themselves or others if not supervised properly.
So sure if we ignore the fact that the OP is a human being and she has human being needs like to eat, sleep, wash and also has obligations to make sure her children live in a sanitary environment, as well as the fact that on the odd occasion she'd probably like to do something for herself once in a while so she doesn't feel like a robot who's sole purpose it is to serve then yeah she could probably get a job in school hours term time only if she was extremely lucky and lived in an area where these jobs exist, which isn't many places.
Then you've also got to factor in school refusal and behaviours that the school cannot manage, the dysregulation before school that is unpredictable where you can't get your child into school until they're regulated, you've got the middle of the day phonecalls from staff saying that your child might be unwell because they don't know what else could be wrong and they've tried everything, you've got the bimonthly meetings with this senco and that senco where one arm doesn't talk to the other so you've got to do all the paperwork yourself to evidence your child's needs due to staff shortages and turnover and a corrupt SEND education system.
And at the end of it all you might also have other dependents that deserve some of your time so they don't feel like glass children, so your available time to catch up on your own needs is a very broken and limited window of opportunity.
If you don't need to take from the pot then you are privileged. Either privileged to have the income to support your family without relying on the state despite your children's disabilities, or privileged to have children with no disabilities.