Sayuri tells us that, as Chiyo, "Inside this tipsy house I lived something of a lopsided life" (1.1). That's a mild way of putting it. Her parents are basically useless. Her mother can't help getting bone cancer, but her father gives up and sells his two daughters to a village fisherman. That's not good parenting.
But, just to play geisha's parents' advocate, what other choice did he have? Could he have raised both his daughters? Or do you think Mr. Tanaka tricked him, and that dad thought Tanaka would adopt his daughters? We have a feeling dad knew the truth, which is why he never told his daughters what was going on. In this case, though, what they didn't know did end up hurting them.