So a bit of back story, my IL's never say no to anything they really should and are constantly being taken advantage of by my B/SIL and other people in their lives (financially, time wise, etc). They just never say NO and it baffles us because its so clear they are being taken advantage of. They will complain after the fact, but always say yes at the time.
Do you think it would be insulting if we got them a book like How to say no without feeling guilty or The book of No, or something like that? Is that a horrible idea??