I'd like to think I would help anyone in that situation, but if the person (either businessman or homeless) seemed like he fell down because he was drunk or high, I might avoid in case they were mentally unstable. Stuff goes down sometimes.
Besides what you think of the dog's right to life, the vet took the owner's money and did not provide the service he purchased. At the very least, the euthanasia fee should be returned.
A: Do you have a smartphone? Then you already have one and don't need to buy anything!
(yes this is a joke)