my ds2 is about the same age, and every few nights he wakes up screaming the house down, convinced something is crawling on him. i have to turn his light on, wake him up and show him that thgere isnt anything there and it was a dream, then comfort him enough that he is calm enough to go back to sleep, but cant turn the light off after that, else he wakes up worse, so i put the hall light on else ds1 wakes from the light. ive also noticed if the hall light is left on all night, not sure what one but, it either dosent happen, or he dosent need to scream the house down because he can see for himself.
maybe a night light might help?