Hello!!! My child is already 1.5 years old. Every night he wakes up at…

Hello!!! My child is already 1.5 years old. Every night he wakes up at 4 am. I don't know what to do... I'm trying to get him to eat porridge. He doesn't like mashed potatoes or milk. He eats other food. How can I teach him to eat porridge? He doesn't like milk at all. He's lacking D3. Hair isn't growing. Maybe rickets? I give him Aquadetrim and Hemoglobin, but everything is fine in his blood tests. What could it be? Is this normal?