Hi, I am happy to give my opinion but please don't depend on it as the definitive answer, also seek guidance from the mothers group on QL and your doctor, I am not a doctor and shouldn't give firm advice without knowing an awful lot more about the individual. I do believe that a calm routine is helpful and as your doctor said, offer food and then calmly remove it from sight if it is upsetting him. The main thing is not to create a stressful mealtime that the whole family dreads.
Maybe you could try making some soup liquidising vegetables and follow it with a rusk if he manages a few sips. You could try putting it in a grown up cup and allowing him to sit on your knee and take a few sips and then gradually move to the table when he feels secure.

Please ask the mothers for more advice regarding the behaviour, they will know better from bitter experience but he may just be having a clingy stage.
Good luck, JJ