My Son Has Trouble Swallowing Any Food Or Liquid. I

My son has trouble swallowing any food or liquid. I don't know what it is called, but the 'flap' that opens and closes between breathing and swallowing is weak and most of the food he eats goes directly to his lungs. He has lost weight. We blend all his food now, but it still goes to his lungs, not his stomach. He is prone to dehydration and pneumonia. The doctor told me that pneumonia will probably kill him. Is there anything we can do?