Hi, Welcome to Hcm, First of all tonsil and thyroid are two different organs. Enlarged tonsils causing poor growth is not known. However enlarged thyroid can happen in thyroid hormone deficiency and it can lead to poor growth. Before analyzing all that, its mandatory for you to confirm objectively if he is actually having poor growth. No point comparing him with his age other kids, every child is unique. You need to get his height, weight checked correctly and plot it on standard growth charts and if he falls in normal range then need not worry. Children of this age dont eat as parents expect. Make sure he takes nutritious food what ever he eats. Happy to clarify further doubts.