Mama dances, laughs, dances. All of a sudden, Mama is sick. I fan her hot face with a paper plate. Too many tamales, but Uncle Nacho says too many this tilts his thumb to his lips.
The House on Mango Street - Sandra Cisneros
What is "too many this tilts his thumb to his lips"? Is it a metaphor? If it is not, what is it? An action that meaning something else?
Forming a fist with the fingers while extending the thumb upwards then tipping the hand so that the thumb goes to the mouth is, or at least used to be (I haven't seen it in a while), a mime for drinking. In the mime the closed fingers represent a glass or bottle. The more common one these days is to mime holding a large glass and shake the hand a little.
Uncle Nacho is suggesting that Mama is drunk without using the word.
It is not what you'd call grammatical English by any means, but it is not broken English or an nonstandard version or dialect. It is a very informal construction, an attempt to capture in text a set of words and thoughts and gestures and innuendo.
Too many tamales, but Uncle Nacho says too many this tilts his thumb to his lips.
This could be written in standard English, spelling out all elided words as:
(I supposed she had) too many tamales, but Uncle Nacho says she had too many of these (makes a gesture of tilting his thumb to his lips).
The presumption is that Uncle Nacho (or possible the narrator) is make a hand gesture for drinking (implying drinking alcohol). And that gesture is being referred to in text as a thing, a noun, and that Mama has had too many of them (drinks).
The written version is a piece of art that doesn't follow the rules of standard English but attempts to follow them allowing for context and intention and non-linguistic gesture. The form is, in the end, the appropriate way to get across the feeling in text.
I would not try to learn any particular syntax from this.
