> Which is a better use of 50k? To give one adult one extra year, or the same money to reduce child mortality for a hundred strangers in a different country?

The answer to that one is very clear: the G7 have more than enough money to fix both extreme poverty (it's just 40 billion $ a year to end hunger [1]) and access to quality medical care (which is a purely USA problem, everyone else has sorted that out decades if not - in the case of Germany - centuries ago) at the same time. There is no need to pit these two issues side-to-side at all.

> Does the treatment actually reduce mortality, or is it just an expensive placebo?

At least for stuff that's not on off-label use, proving efficiency is a mandatory criteria for being allowed to be sold. And some quackery aside, most of the off-label stuff at least has some scientific backing proving that it can actually help.

[1] https://www.wfpusa.org/articles/how-much-would-it-cost-to-en...

> Which is a better use of 50k? To give one adult one extra year, or the same money to reduce child mortality for a hundred strangers in a different country?

Better for whom? Morals are always subjective to your point of view. While points of view of different people sometimes, and even quite often, align with each other enough so that we can talk about shared morals between them, they don't necessary do this all the time. Especially in a scenario of allocation of limited resources.

In the end the only thing that really matters, though, is the point of view of the person who owns these 50k, and nobody else's.

"Which is better" would be a great question if those were the only two things we spent our money on. In reality, both are better than many other ways we spend our money.