Because

- Snopes is easy to use and

- usually Snopes has an almost-identical article about each e-mail subject that my friend sends me. So he would, if he checked, see his own e-mail subject and content highlighted with a big banner that said "FALSE" and explained why/how/etc.

e.g. https://www.snopes.com/pizzagate-conspiracy/

I felt both of these would be necessary if he were ever to examine his sources.

Snopes provides links to sources.