I guess, knowing that he isn't likely to change based on what you say to him, the real question is what it does for you to give him a piece of your mind. What are you hoping to achieve? Is it to get him to stop asking you for money? Is it just to unload your anger?
I completely understand the urge to unload. But will it make your anger over it go away? Lessen it? Or will it just feed your sense of indignation? In my own experience, feeding my resentments is often counterproductive for ME.