My 7 year old really struggles with sharing and generally being generous. I remember his older sibling being the same, but learning and then enjoying being generous. 7 Yr old just not getting it! He hates to have to share crisps/sweets etc, and we have to really stop him at dinner from piling 'his share' onto his plate, even though he actually eats very little. He gets quite upset about this, and I find this quite odd. Most recently he was given money to spend on a school trip. When his sibling went on the same trip he bought a little something for everyone in the family. 7 year old bought several things for himself and refused to give sibling anything!
I find it hard to know how to handle this as the whole point with generosity is that it's voluntary. So saying 'you have to' doesn't feel like teaching anything.
This is contrasted with occasional very sincere big gestures. Giving a toy to a random crying toddler in a restaurant, giving his cousin All of his much loved car collection. Seemingly done with no regrets!
He's an energetic child with strong emotions, and I feel if I could get to the bottom of his reluctance it would help. Sorry this is slightly rambling, anyone experienced anything similar?