Depression can occur due to life stressors. The symptoms that you mentioned could be due to depressive disorder. You must consult a psychiatrist for urgent evaluation of ur son. Also, do ask him if he has any thoughts to hurt himself. Suicidal thoughts are common in depression and must be inquired as it is a life threatening psychiatric emergency. Asking about suicidal thoughts doesn't provoke such acts, rather it may prevent it. Talk to your son calmly without being judgemental.