R.K.
Have you ruled out teething I know those 2yr molars can be a terrible time for many toddlers. He might be having some seperation anxiety. My son got tj bear that reads stories and loves it we cuddle up on the rocking chair and he has a story and then I tuck him in tight give him his special puppy turn the music on and the night light and he is out in only a few minutes I stay in the room until he falls asleep though because he will get upset and cry I see no harm in sitting in the room until he's asleep if its seperation anxiety he needs you to comfort him and cuddle him not leave him to cry it out so for now cuddle him and comfort him before you know it he won't want you tucking him in anymore.