The Pharmacist's Dilemma

I'm going to come up with a thought experiment for you. Imagine that we are on a very remote island off the coast of Maine (it doesn't matter which island, just pretend this is the most remote, yet still inhabited island off the coast of Maine). There is a horrible storm going on and it is supposed to last for several more days. Contact with the mainland is cut off and no boats or small planes can risk coming to the island. Let's now suppose that you have only a limited amount of antibiotics, and there is no way for you (The Pharmacist) to get any more antibiotics until the storm ends and shipments can continue. Now, four people walk into your pharmacy, two male adults, each with his young son (for simplicity's sake, both sons are the exact same age). Both children have the same infection (this infection has been going around the island for the past few weeks) that can easily be knocked out with antibiotics. However, if left untreated, this infection is usually fatal. The two fathers who both came into the drug store at the exact same time have prescriptions from local doctors on the island. Both sons are very ill, and each equally needs the medicine to pull through. There is a problem though; you (The Pharmacist) only have enough of the antibiotic for one person's treatment. Each father needs this medicine to save his gravely ill son. The one father is obviously very affluent, as he offers both the necessary insurance copay as well as 10,000 dollars in cash. The other father is obviously very poor, and has neither the copay or any extra cash to offer. The pharmacist is in a very tough dilemma. He has only enough medicine for one of these children, and the time it would take for the storm to end and more antibiotics to be brought over would be enough time for the second child to die from his infection. The poor father continues to beg for you to save his son's life, and the rich father continues to offer you this large amount of cash.  What should The Pharmacist do and why?