L.A.
You know E., as a early childhood teacher and parent educator that's been through all the safety training, and heard the horror stories, I would have to say your safest bet is to move this child into a regular toddler bed and then just child proof the room.
Do you have a safe way to keep him contained to his room, so he doesn't go exploring the house at night?
At this age one of those round door knob sheaths that you slip over the knob, to prevent a small child from turning the knob, should do the trick. Just install it over the door knob, on the inside of the bedroom.
Don't forget to safety proof your electrical outlets and plugs in his bedroom. Remove breakables and smothering hazards.