[JasmineMama]

I'm guessing you've ruled out all physical causes? My DS1 was a really poor sleeper until I discovered that he was too hungry when he went to bed and couldn't sleep all night because his little tummy was rumbling. I had to do guesswork to get there. He is not a good eater, but I've discovered if I give him a snack before bedtime, he sleeps well...if he goes to bed with nothing since dinner (which likely he only picked at) he will wake up and repeatedly ask for water/milk.

Maybe try experimenting with temperature, feeding, clothing at bedtime, etc if you haven't yet.

And millions of DS1 was a bad sleeper for so long, it's a misery.