Maybe he thought his victim would feel better about being held at gun point if she thought the money was going to help a sick kid. Still, this guy's one sick puppy and needs to be off the streets for a good, long time.
I have to remind myself of this sometimes: not every criminal is an evil person. What he did was most definitely wrong, and he's not a good person. But, his son may really have leukemia and he felt this was his last resort to help his son. I'm sure most parents out there would do whatever they had to do to save their kids, he took it the wrong direction. Hopefully he's caught and convicted. "Man, I'm really sorry about your son and I understand why you felt that you had to do what you did, but you've gotta go to jail."