Free birth control, as well as better sex education (which is, from what I've read, hilariously bad in the US) would probably help quite a bit.
And yet considerable of his pain points are about not being able to cater for his child(ren)
Besides, who are you to tell someone they couldn't have children of their own just because they're poor? It's their right to conceive and adopt children, just as it's yours.
In fact, they could easily afford to feed their children and lead a happy life, wasn't it for the rest of the well off society that's making their lot worse than it is, by comparison. Being poor in a rich town is worse, both materially and psychologically, than being one of a larger poor community.
It is their right to have children, and it's my right not to pay for their children. How is it that the rest of society makes it harder for them to feed their kids?
"For some reason"? Is natural selection not a good enough reason that people have this desire?
(d) Humans aren't exactly rational creatures.
True, but not relevant when talking about goals. Reason cannot tell you that your highest goals are right or wrong, only that some action or lesser goal is right or wrong with respect to a higher goal. I think the drive to reproduce is probably a pretty high-level goal, and while wealth has temporarily short-circuited it somehow in many developing countries, that situation doesn't seem stable.
while this is not the motivation for most people, some people are shortsighted enough to think another kid will actually help the situation.