In just three short lines, the poem sketches an old man who drinks heavily, a "wino," and turns him into something strangely luminous. "Lit" is slang for drunk, but it also means lit up, as if by light. The speaker seems to marvel at the idea of reaching such an old age only to be so far gone, which gives the opening line a mix of wonder and wry pity.
The second line is the sharpest. Calling the liver "like a lie" suggests a body that no longer tells the truth, or an organ that is hiding its damage. The final line adds a puzzling twist: the drinking happens "on behalf of the sun," as though the old man is carrying out the sun's work, glowing for it, or burning in its place. I read the speaker's tone as tender and darkly amused rather than scornful. The mood is quick, odd, and a little sad, with a flicker of warmth inside the wreckage.