Sleep Disorder

My 2yr old grandson is having periods of sleep disturbance every night. He seems to be asleep, he rolls his eyes twitches and shouts out episodes last about 2hrs every night at roughly the same time every night.The next day he is very tired and results in him sleeping till late morning. His uncle sleep walks and has done from being small and is now 25yrs old. Also his grandfather has epilespy, could there be a link. Thank you, glucomate