It would be helpful to know how old your son is and whether or not he has any other medical problems.
Night terrors are a very common problem in childhood that may affect 10-15% of children. Typically they begin at the earliest around 1.5 - 2 years of age, peaking around 5 - 7 years of age. Typically night terrors resolve prior to the teenage years. They are characterized by episodes of sitting bolt upright in bed in an apparent panic. Although the child may appear awake, they are usually disoriented and confused and will not typically remember the episode in the morning.
Night terrors, because they spontaneously resolve and do not represent a serious medical problem, do not usually need treatment. They can sometimes be brought on by relative sleep deprivation or stress, so make sure your child is getting adequate sleep is helpful.
I wonder if there is another reason for his feeling exhausted all day, as night terrors do not typically cause exhaustion. It would be more likely for exhaustion to bring on the night terrors. I suggest that you start by making an appointment with your child's pediatrician
to discuss this issue and see what needs to be done.