Teach him early and remind him often about how to vet his sources. Things like making sure you know who's funding what you're reading, what the political reputation of the sites you're reading on are, and so forth.
Honestly, this is probably the single most important internet skill that exists, second only to (maybe) information security / data privacy, and I didn't get my first serious classroom lesson on this until I was in my Master's degree program. This is a skill people need from goddamn grade school these days.
Yes, it can be tedious, yes it can be exhausting, but if you want to understand who is, or could be, pulling your strings, you have to understand how to vet your sources. Never learning to do this is the path to Fox News viewership.
DaedalousIlios