I had a friend who always kept little packets of cheese crackers in her car, and if a homeless person asked for money she'd tell them she didn't have any, and offer them that instead. You could try that?
I had that same problem X) i started giving them my granola bars haha I wish i could give them money when i see them but i need my money too X)
tell him to get an effing job and life.
You say hi ,if hes always on your case for money that you don't have then you explain that while you are happy to help out when you can,there are times you are less affluent too :))