Husband says chemo And radiation are all lies

All My husband talks about 24/7 is how fasting is the cure for cancer. It’s exhausting, no one in our family has cancer nor we don’t either. He said well In case anyone does , you should Tell them to fast. I am like you aren’t a doctor , an oncologist or have any schooling for this. Is there misinformation out there where there is a community of people who talk about this? I don’t get it, I try to move onto other subjects because it’s exhausting to hear all the time. He is convinced we all have been lied to for many years regarding this subject. Wanted to hear thoughts from this community.