Indeed. Emotional arguments tend to be non productive. Also it is of course not just a medical argument but that aspect is one of the central points to it. I think the point about putting God to the test sums up in many respects why having this child receive would be a poor idea. I think the priest acted with a great deal of wisdom in the compromise he has arrived at.
I'm sorry. I have a hard time agreeing to the notion that it would be putting God to the test. My saint consumed Communion which had been spit up by a woman with rabies. He could have just wiped it up and burned it, but he consumed it instead. People were shocked since rabies is very contagious, but he said, "Nothing bad will happen. It is the Holy Gifts." And nothing bad did happen. There are many other cases with other saints and regular people, and no one accuses them of putting God to the test in a sinful way. The Holy Eucharist is a miracle in itself. It is Christ.