Throwing more money at a problem to try and fix it in the way that makes sense in a very surface level way isn't smart when the stuff you want to fund has been shown to be minimally effective.

Not sure what you mean, unless you are saying food and shelter is minimally effective?

Do many poor children in America also feed and care for their families? I think it's still parents doing that. Of course some children may not have secure access to food and care, but they don't commonly provide it for their families on top of that.

It's more blurry than you'd think. 15 year old kids who are blowing off school so that they can make some money to ensure that their 5 year old sibling has enough to eat? That's definitely a thing. I have no idea how prevalent, but not unheard of.

My own wife's school work suffered because she had to spend her evenings raising her younger siblings while her parents were at work. Same with my niece, whose has one disabled parent and one in the software development field. She gets to act as part nurse, part nanny, and part student. Guess which one suffers.

Money doesn't help nearly as much as time, until you have enough money to hire someone else (or not work).

Agreed. Many students are looking after their siblings if not working, or taking grandma to doctors appointments etc. One of my current students missed our meeting this week because he had to bring his grandma to medical appointments and couldn't work much over break because he is working at a call center. A lot of my children-of-immigrant students have to go to doctor's appointments/government appointments (say with welfare worker or social worker or parole officer) to translate because their parents don't speak English and translation is not otherwise available.

Getting a job as a young teen to feed the family is pretty rare overall. Being the parent for one's little siblings because the parent has a second/third job to feed the family is far more common.

Actually it's also pretty uncommon for poor folks to have even a first job.

http://www.bls.gov/cps/cpswp2012.pdf