The best book to ever read on this subject is 'Boundaries' by Drs Cloud and Townsend (they have other boundary series as well re children, dating, marriage etc)
The main point I got from the book is when there is a lack of boundaries, one person is reaping the negative consequences of another persons poor decisions and actions. Other times it can be as simple as allowing people to expect too much of you when you can only give so much and as a result of both scenarios is a huge amount of stress on one person and another continuing to believe that they can avoid the consequences.
My mothers siblings do this to her all the time. For example my older aunt has borderline asbergers. She is academically a very intelligent woman but she has a history of acting very socially innappropriately ie not showering for weeks, not wearing underwear, cutting people off in conversation, thinking the world revolves around her, compulsive hoarding, innappropriate statements. She also goes to church. What she commonly does is call up my mother or grandmother dropping heavy hints of them doing something for her or fix something that she messed up. Now I dont intend to sound cruel like I don't care about her because I do but what wears my patience very thin is that she does it EVERY week. No joking. And if someone refuses her she goes round to their house to cry very loudly outside and publically in order to embarress them or call them every hour to change her request argument. My aunt is 52 years old. I personally think her behaviour is very manipulative as she has been used to people catering to her needs her whole life and it drives me crazy. I know for a fact that she has enough insight to know what she does is wrong, but the only way to give her that insight is to let her figure out her mistakes and to reflect on her actions.
As christians we are called to be merciful, but we are also told not to get in the way of the Lords dicipline, and by allowing people to not reap their own consequences we are doing just that.
Give a helping hand by all means, but before you help out lay down the ground rules so they understand they can't milk your goodwill for all its worth.
