Let him have your pillow case so he can have your smells when he sleeps.
Make some 'Monster-Spray' so he can use it under his bed and i his closet to get rid of any monsters and build self-confidence.
Let him listen to music (at barely audible levels). There are 12 hour relaxing music on YouTube.

Hi! I had a similar situation with my son. For a while we practiced the yoga abdominal breathing to help him relax and also put a humidifier in his room to help with dry air that used to keep him more awake and anxious. I also changed his blanket to a heavier density one to improve sensory feeling. We added two long pillows that we put on each side of the body so when he has the feeling that someone is next to him. He’s now falling asleep in seconds 🙏🏽 around 9pm but waking up at 3am and coming to our bed because he feels lonely. I started 1gram of melatonin this week and over the past days he slept until 5am. Major progress :) Just sharing the strategies that worked at home in case it helps. All the best

My little, 6, still sleeps with me. I tried getting him into his own bed but he loves routine. We play soothing music, I have lavender pillow spray, and when we lay down he likes to watch me play solitaire until he falls asleep. I don't want him to sleep in my bed forever! It's ok for right now because he's still little, but I understand where you're coming from when they're bigger and you're ready for your own space. I hope you get it figured out, and please share when you do, and how you did it... I'm going to need all the help I can get in a few years.