My son is 15 Months old, he sleeps around 12-1 O'clock at night and wakes up around 12 o'clock in the afternoon. Means he sleeps almost 12 hrs continually, in the evening also he sleeps for 1-2 hrs. In between his sleep at night, he drinks mother milk. We are worried for this much sleep, is it good for him because during this time he doesn't eat anything. His stomach must be empty for that duration. What should we do ? please suggest