I often see an old guy going through trashcans in my city. He is at least 70 years old, and I have no doubt about him being homeless. When I see him during the winter i buy him a coffee to go. He smiles, he is polite and is very grateful. He has two dogs with him that follow him wherever he goes. One day I gave him some change and he asked me if I had some leftover food so he could feed his dogs. It was cold outside and he said they were sick and hungry. Honestly, it broke my heart. I gave him some leftover chicken with some bread and watched him through the window. He took just one bite out of the chicken and divided the rest amongst his dogs, he divided the bread on 3 parts. I have never seen him drink or smoke, he doesn't beg for money, cares dearly for his dogs, even when he is in such a tough spot in his life. The guy has a big heart and deserves much more than life gave him.
Do you live in the US? We have a better system north of the border. My point is everything is taken care of here and nobody needs to panhandle in my country. I had more compassion for street people while I was in NYC. I don't mean to come across as a heartless prick. Some people here are either mentally ill or dont know our socialist system, but most people here are selfish drug addicts.
Perhaps you should give him an old tablet and tell him about faucets. It's more hygienic than dumpster diving and teaching an elderly person the basics of computing can make a huge difference in his life. There was an article in Wired about a group of homeless people who would meet at a park with free WiFi and made money on CoinHD and faucets. It's not much, but an extra dollar or two would allow him to buy himself a coffee.