ohforarainyday
I'd be amazed if Harry's ever willing to be friendly towards William
I can see this mattering on a personal, family level and it's always sad when families fall out.
On a non-personal, world stage setting, it doesn't matter how Harry feels about William.
Unless there's a huge upheaval (and there may be), William will be king of the UK and and an important historical figure in his own right with everything that comes with that, financially and socially.
Harry won't and may find it more difficult to forge his own way if he's kept on the outskirts of the royal family.