As someone so eloquently put it
"I'm knackered. Going to bed at 2am last night was a bad idea." is unlikely to have much impact on boys.
Thinking back to when I was the only 'young one' left at home and my Mum worked shifts (Dad died ~8 years earlier), so might work from 07:00 or finish at 22:00, leaving me to do what I wanted, I remember sometimes being up until gone midnight (listening to shortwave radio) or up before 6am doing the same, in the attic (so had to go on tiptoe not to make a noise!)
I was 16 when I went to college, so was definitely younger when this was going on. There weren't the range of TV shows or games machines (I was nearly out of my teens before the Atari 2600 came out), so did I do much school work - hell NO!
I took Maths and English Lang in '74, took another 9 'O' levels in '75, and only passed 5 of them, and even managed an 'unclassified' (in Latin, as I didn't especially like the teacher, our head!). Most of my class, even the 'thick' ones, got 10 or 11, so 7 was pretty poor.
So leave it to them is, if they want to not do well at school, one way of letting them go on, while setting some boundaries probably works better.
PS for those who turn off internet routers at night, it's generally a bad idea as it will often make the exchange slow your connection down (can be as much as 50% slower).