Meanwhile, Cathy has become a prostitute at the most respectable brothel in the city of Salinas. She renames herself "Kate" and embarks on a devious – and successful – plan to ingratiate herself with the owner, murder her, and inherit the business. She makes her new brothel infamous as a den of sexual sadism. She is not concerned that Adam Trask might ever look for her, and she has no feelings whatsoever about the children she abandoned.
Whatsoever seems to be an adverb as in the case of Oxford (I have no doubt whatsoever); and the prepositional phrase, "about the children she abandoned," to modify feelings (or complement feelings). Is this right or do I have to see other ways?