C.A.
If you know he is safe and fine, go back to bed yourself. Don't stay up with him. Make sure it is dark where he sleeps.
Hopefully, you will be able to get the rest you need so that you can work at keeping him awake during the day.
This will probably take awhile to become the new pattern, but if you stick with it and are firm it should work.
If the alarm clock problem is something that happens as a pattern, place the alarm clock somewhere that you have to get out of bed to turn it off and then don't allow yourself to go back to bed. I find that the first couple moments of my day are the hardest, and once I'm up at moving I'm much better.