So I am awaiting the third book from a Christian relative sent to me since becoming an Atheist six years ago. I have been unfailingly open and read both previous books cover to cover. I plan to do so with the third. I responded to the previous two with the basic message that they were unconvincing and perhaps they should consider that what they believe is false and should be rejected (never get a response to that last bit)
Has this happened to anyone here and if so, what did you do?
If you are sent a book as a gift, you're not obliged to read it. If you're given a sweater, you're not obliged to wear it. If you're sent a sweater you dislike, the appropriate response is "thank you" (and in some cases if you can avoid causing offense, thank you but it's the wrong size or you're allergic to wool or whatever to avoid future waste), not "I'll only wear the sweater I dislike if I can give you a sweater you dislike and you wear it"
Now, if you get sent an average of one book every 2 years from a relative who (I assume) you get along with otherwise, they're motivated by concern for you, etc., then for you to choose to read a book you're not interested in every 2 years is nice, and suggests an open-mindedness, but it's not necessary (I suppose if it's a close relative who taught you to read and saved you from drowning, you might feel a stronger obligation...).
I'm devoutly religious, and I think it would be wrong of me to ignore something that might challenge my faith (that would be closed-minded), but that doesn't mean I'm obliged to read everything that anyone anywhere says I "should" read because it proves/disproves/whatever a set of beliefs/disbeliefs.

I've read some Dawkins and some Hitchens, and if someone I know/like/respect recommends I read something by Hitchens I will, unlike Dawkins (I gave it a chance, to my reading he's nowhere near as good a thinker/analyst of religion as Hitchens or many other less-known atheists were/are). I recall some people saying their faith was challenged by the Da Vinci Code, which I thought was incredibly stupid (if a clearly fictional novel makes you lose faith, I don't think you really had faith), I prefer to read series in order and the first one was so stupid and unscientific in a number of respects (and made false claims about antimatter in the preamble, e.g. saying the only difference was charge, ignoring other properties such as spin), that I saw no reason to read another crappy book by the same author.