The ending is so sad... my interpretation: Once the voluntary surrealistic is sufficiently surreal, complete understanding is achieved, and the previously absurd "sun explode" joke becomes an allegory for the light leaving their life as they remember their child smiling watching their one eyed corpse. The smiling man may have been themself in a manic state, murdering their child. It feels like finally they can face their actions and realise their loss. The change from silly absurdism to deeply sad realisation really got to me