You have done a good job, and so have his parents if he is mature enough now to manage on his own.
Please do not drop in. Doing so will make your grandson feel you don't trust him, and make his mother feel you are undermining her authority, as she has given him permission to be on his own.
Both of them have your phone number and know they can phone you if anything crops up to worry them. They are far more likely to do so, if you accept this new development gracefully.
He is fifteen - next year I believe in the UK he can leave home permanently if he wants, so spending the Easter holiday without supervision whilst his parents are at work is a good thing.
Would you think it was odd if a younger person wanted to befriend you?


