How does the author use the figurative language of “coins” and “rain” in both the opening and closing lines of the poem (line 1 and lines 20-21) to develop the poem's meaning?

In "Abuelito Who" by Sandra Cisneros, the poem opens with "Abuelito who throw coins like rain/ and asks who loves him" and it ends with "is the rain on the room that falls like coins/ asking who loves him/ who loves him who?"

The figurative language used is simile. In line 1, the coins are compared to the rain, and in lines 20-21, the rain is compared to coins.