Got a couple of ideas we have used

mattress on the floor in your room - if/when he wakes you lie on the floor with him then get back up into your bed - once he is comfortable here you gradually move the mattress closer to the door, out the hallway, into his own room - like a travelling caravan (that's what we used to say)

Put a single bed in his room and go and sleep with him. Same concept - once he is settled get up and go back to your bed.

Also how does he fall asleep? If he is used to you laying with him when he falls asleep than you might need to change this as he will be waking expecting you to still be there. We would lie down until DS was almost asleep then move to sit on the floor beside him. Pat, reassure - until DS was comfortable going to sleep with us beside him.

Hope you get some sleep soon :-)