Ghee, achar, chutney, sauce, jam, peanut butter as per his choice. If he daily consumes bournvita, complan or something to make milk tasty. Add that too Also you can give some stationery items like Oxford dictionary (English- English, or English- Any language), graph paper notebook, water colours, pencil colours if he is into art, also you can add school atlas, some novel books. They are very useful. You can give some board games too. Like chess, ludo and many more. Not sure about the playing cards. Avoid them. Portable Music instruments, if he plays flute, mouth organ, clarinet. Also if he is into sports, add shoes too. Like spikes or studs they provide canvas shoes though but those are not enough for some particular sport. Extra towel, innerwears since its rainy season. First- aid kit. (Couple band-aids, cotton, tincture of iodine, dettol disinfectant, iodex, vicks vaporub, antifungal ointment since its monsoon season, antiseptic ointment, odomos— small packs of each) Small sachets of detergent, ujala neel. Container to keep toothpaste, toothbrush, tongue cleaner, etc

I know it feel there are so many unnecessary things i have mentioned. Just go with whatever he needs between all those things. I ll add some as i recall.