+0
Joe met a person who had been sick for three months. -- To me, this tells me that it could be that he could have been sick for three months but not any more, but it also could be that he had been sick for the past three months, up to the present moment.

Joe met a person who had been blind. -- To me, this tells me that he had been blind in the past but should not be blind any longer.

Joe left the house, but before he had reached the place, his wife called him to call John. When he got to the place, he used a public phone nearby to call John. He used some change he had in his pocket. -- To me, the underlined past perfect tense tells me that his wife called before he got/reached the place, placing the calling before his getting to/reaching the place. I think the past perfect tense is used to make that sequence clear and has no effect on the rest of the setences. (I am not sure I have written correctly to reflect what I wanted to say, though)
+0
AnonymousJoe left the house, but before he had reached the place, his wife called him to call John. When he got to the place, he used a public phone nearby to call John. He used some change he had in his pocket.

You don't really have to use "had reached". The word "Before" obviates the need for "had reached", because it's evident that he was still on the way to the place when his wife called him, he was perhaps driving his car or something else.

Just a curt "before he reached" would do it.

+0
AnonymousJoe left the house, but before he had reached the place, his wife called him to call John. When he got to the place, he used a public phone nearby to call John. ...
Your examples would be easier to deal with if you used fewer generic words like "the place" and more specifics like "bank", "post office", or "supermarket". One asks "What is 'the place'? What place is it?" and the last thing you want is for your reader to be distracted from your real question by such puzzles. Also, the repetition of "call" is distracting. Try substituting "contact" for one of them, thus: "his wife called him to tell him to contact John". That doesn't answer your question, but you might want to keep it in mind the next time you construct an example for discussion.
________________

Now for the question. The past perfect, say the grammar books, is used to indicate a time prior to a reference time in the past.

When I met the famous author in 1998, he had already written five novels.

The clause with the past perfect occurred first. So he wrote the novels, and later I met him.

Same idea: I met the famous author after he had already written five novels.

First, he wrote the novels. Then I met him.
______

Now look at this strange example:
I met the famous author before he had already written five novels.

The past perfect indicates that he wrote the novels first, and then I met him. But the word before completely reverses that idea. It says that I met him first, and then he wrote the five novels. We ought to conclude, therefore, that the past perfect is never correctly used in a before clause.

And yet the past perfect is quite often used in a before clause. How can that be? The answer is that the past perfect is used in a before clause to indicate the non-completion of the action or the interruption of the action. In this case the usual use of the past perfect to indicate a time prior to another past event does not apply.

Before he had reached his destination, his wife called him.

Here his wife's call interrupted his progress toward his destination; it prevented him (temporarily) from reaching his destination. The call occurred first, not the reaching of the destination. We don't even know for sure if the destination was ever reached just from the information in this one sentence.

It is perfectly OK to use the simple past instead, of course:

Before he reached his destination, his wife called him.
________

In your series of sentences, you are correct that this use of the past perfect does not disturb the meaning of the other simple past tenses.

CJ
Site Hint: Check out our list of pronunciation videos.
Comments  
You've got it!
 MrPernickety's reply was promoted to an answer.
 CalifJim's reply was promoted to an answer.
Students: Are you brave enough to let our tutors analyse your pronunciation?
Thank you, every one. Of course, that includes CalifJim for his excellent reply.