At 7 months, you should never give over-the-counter cough and cold medicines, as they can cause serious side effects in babies. Since his symptoms are frequent and persistent, please return to your pediatrician or seek a second opinion. He needs a professional evaluation to rule out allergies, environmental irritants, or asthma-like conditions. For safe home relief, use saline nasal drops and a bulb syringe to clear his nose, run a cool-mist humidifier in his room, and keep him well-hydrated with breast milk or formula. Do not start any new medications without a doctor's direct prescription.