I don’t understand how going to bed early is a problem.
My high school started at 0800hrs. I had to be up by 0630hrs to catch the bus at 0715hrs, and it was a 15-minute walk to get to it. I went to bed some time between 2130hrs and 2230hrs almost every night like clockwork.
Did I get 10hrs of sleep? No. But the ≈8hrs I did get was enough to ensure I was awake and coherent in the morning.
If kids are tired in the morning, what’s stopping them from going to bed earlier? I was never forced to do so. I just did, because I was getting tired shortly after 2100hrs. I listened to my body.
Honestly, if we’re talking about mostly or completely surface blasts, and not atmospheric detonations, that might be what saves the planet.
Nuclear winter is very much a thing by how the thrown-up dust reflects most incoming light, and with most detonations being in cities, the kicked-up dust would contain plenty of iron… which is the major limiting factor of phytoplankton, the largest single converter of CO2 to O2. All it has to do is fall out of the atmosphere and into the oceans during the spring to summer. So we need a late winter or early spring nuclear war.