There are no randomized studies on
sleep disturbance in brain injury patients. The
sleep disturbance may last a few days to a few weeks/months. If it does persist, I would advise getting a sleep study evaluation to ensure he has not developed sleep apnea.
It is also important to recognize that post-concussive symptoms may also include headache, dizziness, memory challenges, difficulties with concentration, fatigue, depression, anxiety, and increased or decrease in sleep.