He cannot, except some feel-good and virtue signalling slogans. The resources for social support in most developed countries are limited even for their own citizens; taking anyone would quickly overwhelm the system, that's a basic math, even without a napkin.

For people, who do not have a good visualisation skills for numbers, there's this video: https://www.youtube.com/watch?v=LPjzfGChGlE

The point is, if you want to help the people in the rest of the world, you have to help them in their countries, which I wholeheartedly agree.