Because he has a condition fewer than twenty people in the world have and the leading physician and researcher for that condition is in the US (the doctor who went to the UK to examine Charlie).
That’s nuts. There are children getting their heads chopped off in Syria and Iraq. Why not give them residency? There are children in China who are used to harvest organs, why not save them and bring them here?
Why this kid? What’s so special about him? Why are we spending our tax revenues on him and his family?
“the leading physician and researcher for that condition is in the US”
Key word here: “researcher”. Being able to treat Charlie could result in better treatment both for Charlie and others down the line.