That is terrible and I am glad someone broke ranks to inform you of the risk.

My wife had a very agressive triple-hit lymphoma and CAR-T was eventually suggested. Fortunately, the medical team was very honest about how hard it impacts your body, with very likely chance of death. My wife decided to do it, and it almost killed her. The team actually had to "shut down" the process, so she didn't benefit completely from the treatment. The suffering was pretty immense as well. She died a few months later regardless.

We are (were) both engineers and we did wonder how many might get streamrolled by the whole medical process, where you do get this odd combination of extreme indifference and optimistic exuberance.