Hi D.,
My daughter did that for some time, it is really bad cause you are exhausted! The best that works for me is feeding her something warm and back to sleep, I nurse her until almost 2 so I had to nurse her and sometimes let her sleep wherever she fell asleep because I couldn't move her or she would wake up again.
I think that you have to train him, give him a bath with camomile or lavender oil before bedtime and a huge cereal or milk warm and see if he last longer, otherwise, try feeding him when he wakes up and try to get him back to sleep, he has to get use to. He is not the boss and he doesn't know unless you teach him.
Babies don't know hours, you have to tell them when to do what. It takes like a week but it works, be consistent.
You can also try with camomile tea, it is good for them and sometimes help them to sleep better.
Avoid long naps, let him crush at night really exhausted, at least until he gets it.
And for you...well....go to sleep when he goes, so you can catch some sleep too.
The best of luck and let us know how it goes!
Mariana Abadie
www.MyKidsFirst.com