Oh you poor thing, it sounds so exhausting . Could he be teething?

My DS2 went through a night waking phase, it didn't last thankfully! A trick that helped was - I put a Fisher Price Ocean Wonders Aquarium cot toy in his cot. It plays music and has lights and bubbles. I told him it was his special bedtime toy and he could play with it when going to sleep and when he wakes up at night. If he woke overnight crying I would go in and turn the toy on (he knew how to do it himself too) and he would quietly watch it before falling back to sleep. He eventually stopped waking up again. It might be worth trying something like this?

I hope he goes back to sleeping well for you soon .