Talk to Pediatrician on Underweight One Year Old

My baby boy born at 36weeks with 1.8 kg. Now at 1.6 year , he is 8kgs, height is 30 approx. MashAllah active,quickly burns his calories. He has six teeth, upper(four), lower(two) Does not chew. I give him puree food. Now, guide me with some nutrition foods or meals. N also help me out to select milk from the store, which milk to buy for cooking for him. ( the local bhens ka dud or any low fat milk like "Almarai"). JazakAllah for helping in advance. May Allah make ease for those, who priovide ease for others.