There is no evidence that any form of so called alternative medicine (SCAM) has any effect on the course of lung cancer.
So whatever claims this person makes, or whatever testimonials he may have from satisfied customers, it is baseless.
You don’t say if your father is actually under treatment by a real doctor (oncologist). People often in desperation turn to alternative quack healers when they fail conventional treatments, or sometimes in addition to it “just in case” there is something to it.

Google him