Question

I don't understand this poem, and I read it about 5 times.

Answer 1

Firstly, I think you may have written a word wrong "umaswerable", and I'd like to know what word actually should be there? Secondly, I'm not that familiar with that part of the world (Mexico), but from the poem I would say they were on the run (trying to flee their country) or just were living in the car, because they didn't have enough money. Both could be true, the first one at the beginning and the second one after. The boy clearly suffered some sort of trauma (at age 7) and may even have lost a hand ("one small hand") and they have had a rough time since ("umasw... woes").

Answer 2

I get you this poem is confusing and hard to understand. You have to read it several times to truly understand it. Ok but next time you don't understand a poem that has a complicated language copy the text and go to rewordify.com. Paste it. It will translate all those complicated words to simple words. Try it. 
 
Nye describes her experience being comforted by her mother when she was sick. Her mother told her she was not dying as long as she still had the strength to make a fist. Nye then writes that she is still comforted by this thought.

The poem has several devices such as:

Allusion it can be applied because it refers to a past historical event.
Imagery because it describes in detail the palm trees. Among other things. 

The tone is nostalgic because she is looking back on she was traveling but she also uses a tone of pride because she survived the journey and she can still make her hand into a fist .