Parts of 24:18-24 sound like what the friends have said. Whose words are these?

By the book's headings, Job's. The last heading was "Then Job answered" (23:1), and the next is "Then Bildad the Shuhite answered" (25:1); nothing in chapter 24 names another speaker, and the WEB closes the quotation only after "who will prove me a liar, and make my speech worth nothing?" (24:25). Some of these verses are close to the friends' words. "Their portion is cursed on the earth" (24:18) sits beside Zophar's "This is the portion of a wicked man from God" (20:29). "He will be no more remembered" (24:20) sits beside Bildad's "His memory will perish from the earth" (18:17). "They are exalted; yet a little while, and they are gone" (24:24) sits beside Zophar's "the triumphing of the wicked is short, the joy of the godless but for a moment" (20:5). Some are close to Job's own words. "The worm will feed sweetly on him" (24:20) sits beside "The worm covers them" (21:26), where worm is the same Hebrew word, and beside "The clods of the valley will be sweet to him" (21:33), whose sweet is the verb Strong's derives 24:20's feed sweetly from. "God gives them security, and they rest in it" (24:23) sits beside Job's "Their houses are safe from fear" (21:9); in the Hebrew of 24:22-23 the subject is he, and the WEB supplies God. The book doesn't say how 24:18-24 fits beside 24:1-12, where the wrongs go on and "God doesn’t regard the folly" (24:12). Readers take these verses in more than one way. These notes keep to the book's headings, which give every verse to Job, and don't decide how he means them.