Is that a question from your grandson
@Susannemary or have you been diagnosed Type 1 too?:
https://forum.diabetes.org.uk/boards/threads/newly-diagnosed.104115/
People on insulin need to inform the DVLA and fill out the appropriate medical forms. A short term licence will usually be issued that will need to be renewed every few years (usually 3 years). IMO anyone recently diagnosed should avoid driving anyway for a few weeks until they get used to the insulin and diabetes.