Hi. My 17 Year Old Son Takes Epilim 500mg Twice

Hi. My 17 year old son takes epilim 500mg twice a day and has done for 3 years. He has forgotten to take the medication in the past with no issues. This evening he has taken his medication twice, therefore he has had 1500mg instead of 1000mg. He is very fit, 5"11 and 12stone.

I am assuming if i stay in his bedroom tonight and monitor him.