There is a meaningful difference between knowing that gene therapy can cause serious complications in general and being told that every treated monkey developed moderate to severe liver damage, with one also showing kidney damage consistent with the mechanism that ultimately killed the child. Informed consent was pretty hard to get here
The main issue is the hospital ethics committee signed off on a private clinical trial based on early positive results, but before the final toxicology report was finished... the whole program in China is about commercially funded research (meaning it didn't go under the usual Chinese FDA-type review which is more thorough). This family was privately paying for studies on mice and giving the doctor hundreds of thousands of dollars to explore this avenue. It also says he did share the toxicology report with family beforehand and they still went ahead with it anyway. This is the report showing a monkey died of liver failure, the same thing that ended up killing their daughter.
I believe it was a very dumb idea to use their kid in something very experimental, especially in China. But lets not pretend the family didn't play a huge role, with many chances to have it double checked with other scientists before putting their daughters life at risk. They 100% had the means to do so but chose to gamble.