[user104658]

Originally Posted by bitontheslide

if they want to discuss things or not ... they still have plenty opportunity outwith the funeral. Personally, i think there is a lot more behind the rift between them than is public knowledge. When Harry chose to have his own charity separate from Will's, some disagreement led to that parting, and that happened long before H & M stepped down

Most likely (although disclaimer; I obviously don't know) is that it's down to William being in line for the throne. Harry feels a lot of anger and resentment over the treatment of Diana and ending up without a mum at a very young age, William can't really afford to hold onto feelings like that because he's destined to be at the top of it all. You can see why it would lead to frustration, on both sides.