Of course you have a right to be. You need to distance yourself from your family. You'll find the right people will come into your life at different times but even until then if its just you and your son most of the same, and you're gonna be happy(!) and able to focus on his nutrition needs and do right by him. Obviously make sure he is eating enough, ask your pediatricion if he is getting enough calories. We let my guy eat as much as he wants. He is naturally small as well and I get a lot "omg he's tiny!" comments which are annoying. You sound very invested in the wellbeing of your son. Continue to seek advice and different opinions from medical teams on whatever your aons symptoms are and his food intake. Good luck! Definitely distance from anyone in your family who is not supportive and sensitive to you.