How is his tummy overall? Is he having healthy, soft bowel movements? This age is ripe for constipation which wrecks havoc on sleep. You can try a supplement like UnWind (tastes like watermelon !) before bed, and diffuse either Seedlings Calm or Sleepyize in his room at night. It is also the age for monsters in the closet, so if he’s mentioned any scary things -maybe a monster spray with some calming essential oils like Lavender that he can squirt around his room.