Sounds like he's sick, poor thing!
There are lots of things going on, from the sound of things.
That's great your DH is helping out. With luck it's just one of those things and will pass with time, sometimes it's just a matter of riding it out. Is it an option for your DH to sleep elsewhere for a bit so you can bed-share with your DS if it's like this for a little while? It's always easier if you don't have to get out of bed.
Hope you get a good rest tonight!