Too sick - or well - to die

Yossarian toyed with Milo about his "syndrome."

Yossarian's syndrome, as he calls it, is named Garnett-Fleischaker syndrome, and it's a liver condition. Yossarian likes his syndrome because he can earn money from it. Further down the story he thinks about how the only secret he won't tell Milo is the location of the hills where he keeps his money buried from all the trading he's done with the dried fruit he's given. Doc Daneeka gives him all the dried fruit he wants becomes he has a liver condition -- it doesn't matter if he actually has it or not, just Yossarian saying he does is enough. He tells Milo that dried fruit is good for him, that's why he doesn't eat it. He wants his condition to live out longer and that's why he doesn't do anything to stop it, including not eating anything good for him. Yossarian wants to keep it because it gives him a chance to give it off to anyone else who wants it, and those people end up doing whatever they want with it -- in Yossarian's case, he earns money.