> * Took hundreds of thousands of dollars under the table to develop the treatment

I'm in two minds about this.

On the one hand, at face value the funding and payments seem dubious - especially with the mention of one of the doctors returning his payments, suggesting they were for his personal enrichment, rather than payment for the costs of the treatment development and trial.

On the other hand, the parents were literally funding the creation, for the first time ever, of a highly complex treatment essentially custom-made for their daughter's condition. This required a lot of detailed and expensive science, with the generation of a mouse model of the disease, followed by development of the treatment, and then the testing of this in monkeys. In US/EU, this work would likely cost millions of dollars/euros, and it's not unreasonable that it would also cost a significant sum of money in China.

Yeah, I was also surprised by how inexpensive this was.