Wow, that's not much sleep. Kids need sleep because that's when the body is shut down. The brain is using minimal power to run the body, it's just keeping the heart beating and air moving, etc.... Sleep is the time when our bodies fight off disease, kills germs the best, and repairs damage to it.
We must sleep or our bodies will be weakened.
I'd honestly talk to the doc about a sleep aid. We did this for my grandson that is ADHD. He would often stay up until 3 or 4 then be back up at 7 or 8. Knowing how damaging this is to his body I talked to his psychiatrist that treats him for the ADHD. She was leery of giving any sleep aid to a child this young but she know me and how I manage meds. I take minimal doses. If it works I never use a full dose.
We give him half the dose she prescribed. He can take a whole pill, every night. I give him half a pill only when he's bouncing off the walls and isn't able to fall asleep in a dark room with a full tummy and every little thing we can think of that would relax him and help him to fall asleep.
Taking a sleep aid has been a good choice for us. He wakes up after taking it the night before and he's a much happier boy, he's rested, he's just better off.
It's a big decision but please talk to the doc about it. 2 hours of sleep a night is not healthy for any child. A child this age should be going to bed by 9pm, sleeping all night unless there are extenuating circumstances, and waking up around 7:30 or 8. Then taking a 2 -2 1/2 hour nap in the early early early afternoon.