Private surveillance, quantum and disease

Hello Rabbi, regarding free choice, why can't it be claimed that God intervenes in places where there is no completely free choice and no statistical change, such as diseases, viruses, things that in reality are difficult to test and see? I have a friend, for example, who got cancer as a child and recovered (blessed be God?) and said that he certainly received it from God.
Here, the attempt to change the statistics also doesn't work, as the statistics of cancer are constantly changing and it is not even clear to science when the immune system will lose or succeed in overcoming the disease.
The same question can be asked in quantum terms, although one could say that if he intervenes at point A, it will necessarily be at the expense of B, otherwise there is a change in the statistical nature here. But regarding diseases, I am interested in what the rabbi has to say.
Thank you very much.