Wide awake during the night for hours?!

[AndThisIsTrue]

My DS has just turned 2. He has never been a good sleeper and since he was about 9 months old he has been waking up and being wide awake for hours during the night. It's not every night but probably 4/7. It seems to be getting worse though, Last night he was awake from 1-6am!!
He's not upset for most of the time, I don't put lights on, I don't talk, he mostly stays in his cot tossing and turning or talking to his teddies. He sometimes has milk in desperation but even that doesn't work most of the time. He only sleeps for about 10hours a day including a nap which doesn't seem like that much and I have even tried dropping his nap completely recently but he just sleeps for 9 hours a day instead.
Help! I have no idea what to do with him and I'm so tired!

Ds 2.8 does this- he either sleeps through or wakes and is awake for hours( it's so tiring and frustrating) he did it most in a nap transition. He no longer naps and it's got better - so maybe once a week!
It's often when he is overtired. Luckily he often does it on Saturday nights now so we can catch up with slew on Sunday morning at least after being awake for s long time last night he woke for the day at 10.15 when my shower woke him.

Thanks for replying, I'm glad its not just me that has this problem! What do you do with your ds when is awake during the night? I feel bad that DS spends 2-3 hours in the dark in his cot but I don't want to make it interesting in case he starts waking up more!
I'm not sure whether to persevere with dropping the nap or if him being over tired is making things worse. How long after stopping naps did you see an improvement?

If he's happy enough playing away in his cot leave him to it go back to sleep if your engaging with him even if it's in the dark it's more entertaining for him. Also I'd try waking him in the morning at the same time even if he's only been back asleep an hour and also wake him from naps during the day - let him have a good nap but I'd be tempted to wake him after 1.5hr and then having a set bedtime. Keep to a strict sleeping routine it might be hell for a few days because you'll both be shattered but it might work.