I think my friend Allison Bottke's book, Setting Boundaries with Your Adult Children, has recently become the book I have most recommended (and given away copies of) in the last couple years of my ministry.
It is heartbreaking how many marriages and families are fractured by the destructive and manipulative behaviors of an adult child (or sibling, parent, etc.). Allison's book is a gripping, vulnerable, and practical account of how she learned the hard way to set boundaries with adult children and bring about health rather than guilt, abuse, and destruction. It outlines a workable alternative to the enabling relationships many of us think are normal, a way to restore sanity to lives that are spinning out of control:
S = STOP Enabling, STOP Blaming Yourself, and STOP the Flow of Money
A = Assemble a Support Group
N = Nip Excuses in the Bud
I = Implement Rules/Boundaries
T = Trust Your Instincts
Y = Yield Everything to God
Even if you don't feel like you're being dragged down by the burden of trying to help an adult family member, you know or minister to someone who does. This book can be a life-saver to that person. Get it in their hands.