Well, he then started his “own” church.
Anyway, whatever his personal beliefs, chlorine dioxide is dangerous and should never be ingested by people.
“About 5% of large water-treatment facilities (serving more than 100,000 persons) in the United States use chlorine dioxide to treat drinking water. An estimated 12 million persons may be exposed in this way to chlorine dioxide and chlorite ions. “
https://www.atsdr.cdc.gov/phs/phs.asp?id=580&tid=108
Remember, hypochlorite is a chemical naturally found in all human granulocyte cells and is used to kill infectious microorganisms.
So the answer to whether chlorine dioxide can be used for health purposes is probably a yes.