When thunder strikes, some bolts of voltage(electrical currents saturated in the atmosphere) passes through a body e.g buildings, trees, rocks, metals, cars, structures and sometimes humans. Although, only few people lived to survived thunder striking them, because the thousands of jolts of electrical energy could vaporise anything depending on the quantity/volume the body takes.
Not all Lightning comes with a thunder and vice versa, this is to tell you that nobody would intentionally want to be in a thunder path to get a strike. Its swift, just only a few centimetres in diameter, but comes with a brightness equivalent to 1 million 100-watt bulbs per metre and a temperature of up to 30,000 degrees, this means death in most cases for any living thing that gets caught in its path. Now, not all thunder strikes carries devastating and Hazardous bolts, these bolts of thunder actually could change body structures, alter DNA and that is why some people who survived have experience incredible changes like becoming geniuses, or even cases of medical ailments cured. The human body has some electrical charges, the body structure is made up of electrical components and the interference of external payloads could be damaging to the body or could reconfigure the electrical structure of a body systems.
The mystery is that the pre-lightning can't be seen with the naked eye and can not be predetermined. Pre-lightning is the route, a charged channel that develops from the cloud towards the Earth in a split of a second before the eventual discharge. From the Earth or the surface of the Earth, small charges are released towards the clouds. This is one of the factors that determine where the lightning is going to ‘strike’. If that could be ascertained, most people with body aliments might want to try out their lucks with natural electrical treatment, the problem is that, the quantity a body needs is not known. So when a body carries like charges(either +ve or -ve), depending on the charges Carried by the lightening during a thunder storm, it could get hit by a thunder bolt.
If known, cancer cells(some degree of cancer) in the body will not survive these electrical charges. A thunder bolt could carry millions of volts, just a tiny percentage of that is sufficient to kill external and terminal cells/diseases in a body. To experiment this, any external wound on your body will start healing up if you ever get shocked(electrocuted), this is not a recommendation.
The big "if" is, you can't gauge or calculate the strike paths to place a cancer patient there, you can charge up your body or clothing with specified gears but it could be hard to calculate the bolts needed to cure external cells in the body. If you manage to read to this part, then you will understand the topic better!