"Brain Damage," by Tom Leins, in Coming Through in Waves: Crime Stories Inspired by the Songs of Pink Floyd, edited by T. Fox Dunham, Gutter Books, 2021.
Rey is out of prison but he visits Barrett there because Barrett saved his life once. Of course Barrett wants a favor: "My wife's sister is missing." She was thrown down the stairs by her ex-boyfriend resulting in brain damage.
Rey finds out that the wife used to work at sex parties for a crooked lawyer named Thorgerson and Thorgerson used to take an interest in the little sister. Maybe too much interest...
A hard-boiled private eye-type story with an unusual protagonist. A lot to recommend it.