All the faith he had had had had no effect on the outcome of his life. You can think of the sentence like this: All the faith that he had had (in something/someone/himself) had had no effect on the outcome of his life. Both uses of "had had" are the past perfect *had* + past particle of *to have*, which is also *had*. The combination seems strange, but you get used to it. The present perfect would be *have/has* + past particle of *to have*, which is *had.* So this one does not seem as strange. All the faith that he has had (in something/someone/himself) has had no effect on the outcome of his life. Or: All the faith he has had has had no effect on the outcome of his life.

Rather than give you a grammar lesson, I'll tell you what they mean by english being "so fun". The phrase "All the faith he had had had had no effect on the outcome of his life" is considered fun because it uses the word had four times back to back and yet the sentence still makes perfect since, in english. You would have serious difficulties trying to replicate that in any other language without sounding foolish. There are other quirks of english that non native speakers seem to enjoy like being able to use any noun as a verb. Examples of this are like when we say "he gunned him down" rather than "he shot him down". Or being able to say "I'll knife you" rather than "I'll cut you". We also use conditions and adjectives in place of nouns as well like "The dead will walk again". The writer of that quote is basically saying that english has a freedom of use and expression that is nearly endless and it's fun to use and examine it.

La pregunta es algo vieja, pero el significado en español es: "Toda la fe que el ha tenido no ha tenido efecto en el resultado de su vida"

Sorry, they are this sentences: Why is English so much fun? All the faith he had had had had no effect on the outcome of his life. Because that sentence makes perfect sense.