Because he would rather give his last bit of money to Buck than any of the other leeches he knows will bleed him dry.
Side note, I love the episode where Buck gets a credit card. Haha.
PSN ID: sled_dogs76
60" Pioneer Kuro Elite PRO151FD, Yamaha RX-V3900 A/V Receiver, Oppo DV983-H player. Coming soon: 2 Seaton Submersives from Mark Seaton