Sorry you are going through this. No real advice, just here to sympathize. I have 3 kids, my older two slept really well. It took my oldest 14 months where he started sleeping all night every night. My 2nd child was the best sleeper ever, and even at the age of 7 she sleeps well still, never one problem. Then comes baby number 3...She is 2 1/2 and is a HORRIBLE sleeper. She was raised and parented the same as the other two, but obviously she didnt read the section on sleeping throught the night

(in the parents manual of course

)
Anyways, at 2 1/2 she still doesnt sleep every night all night long. Its so darn frustrating and exhausting. I am not a big fan of CIO either. We tried when she was younger, and all it did was make her and me and my husband miserable. About 2 months ago, she was going through a habit of getting up 5 minutes after she went to sleep. I was getting annoyed with it, and let her try to settle herself..Well she then started climbing out of her crib to find me. She wasnt having any of that being left alone business. That got her in a big girl bed quicker then we were expecting. Even now we never know how she will sleep. Some nights she goes to bed and we dont hear from her. Other nights she goes to bed easy, and then I find her at my side of the bed at 3am

(Let me we have this extra sitting room inside the master bedroom, with its own door)So when she awakes during the night she is not wandering the hallways to find me.
We do the same routine every night, but its always a crap shoot.When she gets up during the night we let her sleep with us. I firmly say, go lay down and go to sleep, and I hear a little cute voice saying "Ok" and she goes to sleep. If I try to make her go back to her own bed there is a lot fussing and crying going on. This way we all get back to sleep sooner. Sleeping in our bed is not what we had planned, but after 2 1/2 yrs of horrible sleeping, we just all want to get back to sleep.
Sorry I have no words of wisdom for you..just know I do understand.