My sibling likes to read fiction. They’re a comically basic-ass shit-lib. This person says that they don’t like to talk about politics. They always take the bosses side at work, basically a reincarnation of our Rachel Maddow-parroting boomer capitalist fucboi parent.
I know it’s a tall order but: What work of fiction can I gift them that will break them out of their capitalist complacency and remind them that they’re nothing more than a wage slave before they can even resist the indoctrination? I want to be subtle but effective; it has to fly to under their radar.
To give you an idea of how hopeless this little lemming is: this person has been reading Vonnegut lately and legitimately didn’t even know that Eugene Debs was a real person. This person figured it out when I informed them of Debs when they were telling me that no one has ever run for President from a jail cell. 🤦🏿♂️
What's wrong with reading Vonnegut
and not knowing who 
was is just normal. Most people can't name an unsuccessful politician from 100 years ago.
I don't think any text will do what you're hoping, that kind of progress is usually made through conversation. But I'd recommend George Saunders' In Persuasion Nation (2006), which is a short story collection about cranked up capitalist inconsistencies. He's a lib but he's got a good radar for the savage idiocy of a society under late stage capitalism.
Alternatively I might suggest The Fever (1991) by Wallace Shawn.
Based Grand Nagus.