When my daughter was young both of us loved a series of books by Russell Hoban all about a very anthropomorphised little badger called Frances. We both loved them because she could identify with Frances because she did what she did, refuse to go to sleep, be unsure about a new sibling etc and I could identify with the parents as they responded to all the minor dilemmas of bringing up children.
One of the books in the series is 'Bread and Jam for Frances'. All about the time she decided she would only eat bread and jam and how her parents responded.
GeraldineGransnet get it from the library, you will find it soothing and if you read it to your grandson he may recognise himself.
Under the Banner of Heaven ITVx