Again, Darl's sanity or insanity must be viewed in terms of how other people react to him. After all, it was Anse Bundren who declared him insane, but, as has been noted, Anse is not a reliable judge of character. From outside viewpoints such as that of Gillespie, we realize that the uninvolved person looks to Darl to perform the rational action and is surprised to discover that Darl did not prevent Anse from applying the cement. This idea is then doubly ironic when the Bundrens send Darl to the insane asylum.
Vardaman's view of Darl is that he thinks Darl is upset because Addie almost got burned up. Instead, Darl feels the pathos of continuing this absurd trip and is crying because his mother has not been given a cleansing funeral. In all the previous outside views, the other people have expressed the idea that the best way to honor a woman dead so long is to get her in the ground as soon as possible, which is exactly what Darl was trying to do — give his mother a decent and honorable funeral.
