Undernutrition or malnutrition. Is dull.

My son is 2 years 3 months old . His birth weight was 3 kg. His 15 months weight was 11kg and present weight is 11.7 Kg. His muscles looks weak. Even his buttock bones can be felt. He is tall compared to his age. And nothing is according to his age. He doesn't recognise mammi papa. He speaks  some words like chacha chachi bua papa cow . He is fond of watching tv. He doesn't eat healthy. We have tried all changes preferences etc . But all is wasteful for us. He eats biscuits icecream snacks toast . Hardly 1 chapati in a day. And he is obstinate for breastmilk. He eats 1 banana daily. He doesn't drink cow or buffalo milk. Only breastmilk he demands.  He eats 1-2almonds daily. Kidscare multivitamin 5 ml once a day. He eats roasted chana. Most time feel frustrated cranking and over active. We can feed him healthy only on watching cartoon. Else no one can make eat him healthy. I need multivitamin for him which increase his weight. Because his overall development is dull.