He does it because you are not consistent in saying No , you say you are speaking to him about it, its too much, stay quiet, take him back to his bed each time he comes out,dont stay with him . maybe you will have to shut off the living room as I really dont know how you stop that if you are sleeping .
I have a son that is 5 that do the same thing. What me and my husband did was go to lowes and get a night light of his favorite thing like the fish in the sea, and we placed it in his room and he has something to look at until he fall asleep. We haven't had any problems after that, so good luck with that.
Thats a good idea Candy has and you may let him choose which night lite he wants ..that may help a lot ..