Most often loose motions or cough and cold in children is caused due to certain viral infections. Unless associated with secondary bacterial infections, antibiotics are not required. Irrespective of use of antibiotics, it should take 5-7 days and you would have to be patient. Rather than giving Zincold, I would perfer giving paracetamol separately only when he has fever, and cetirizine syrup once daily at night for a few days. You may give Kufnil for 3-5 days. I would prefer stopping it after that. Giving ORS (oral rehydration solution) to prevent dehydration is important. Since most often the loose motions are caused due to rotavirus, antibiotics or any other medicines is not required. You may also give some amount of yogurt/curd as it contains beneficial bacteria. The cough and loose motions are probably unrelated and the cough will not get relieved as loose motion. They have occurred and would resolve independently.