my sister in law have 6 year old boy. he has only 13 kg weight. which type of foodcan eat for increase his weight

A. Hello mam, he can be give foods which are healthy and in the same way they are also high in calories as well such as dry fruits and nuts , eggs if preferred, milk, milk shakes with fresh seasonal fruits , panner , ghee , stuff paranthas, variety of dals , chana , rajma etc , sago , soya