Hi L.
Have you told him that he should stay in his own room while you are asleep? Not that you don't want him in your room, but that he will learn to sleep better in his own space.
By the time you think he is too big to be sleeping with you, he is. That is my opinion! Is his room really his space? Perhaps you can decorate more to his space, but that did not help mine. But just like kids give up pacifiers, they don't go to school with them, kids give up sleeping with you, because they get big they get crowded out. I remember my mom and dad spreading themselves out across the bed so I could not get in. I don't know how old I was but they simply said "I was growing and didn't fit so good". I thought they would miss me. I remember thinking that and since I am now the grandmother, that was a lot of years ago.
My suggestion is to talk about the fear, and to let him have the lights, music, or static noise, whatever helps.
Maybe like mine he doesn't need so much sleep. We let him read with a flashlight, I heard that kids liked that. He did & kids think that is fun. We had to do something as he only slept 2 hours in 24 and I needed more sleep than that.
God bless you and Give you wisdom