allow him one small treat per day - the more you say no the more they want it. Give him a bigger reward monthly to start ig he doesnt steal or hoard food but make it something other than food

I have twin granddaughters who have autism. The high functioning twin girl has started doing this. Over the last year, I began to notice that food items were missing from the fridge. At first I thought my daughter was eating cookies, drinking juice, eating chips, snacks in the fridge or cabinet and a number of other things. Then after I discovered that it was her doing these things and not my daughter and I tried as the grandmother to talk to her about it in a calm soothing fashion, the child still go upset. I told my daughter to keep an eye on her since I work long hours, but with the other twin severely autistic and needs to be watched 24 hours a day, the high functioning twin has a bit more freedom which lead to this snack hoarding. I promise you I am perplexed and have no idea what to do with this issue except stop buying snacks, chips, pop, juice, cookies and see what happens.