My Nephew Has Experienced Quick Onset Of OCD Type Symptoms

My nephew has experienced quick onset of OCD type symptoms and has some sort of eating disorder. He is only 14. This has caused a decrease in his grades so much that he failed the school year. He has sudden outbursts and when he eats he gorges himself. he wont eat the first or last bite of anything. could there be some sort of underlying condition that the drs here are not seeing? Is there testing that his parents should be asking to be performed?