AGA, Alienated Grandparents Anonymous, has been one of the most helpful organizations that I have discovered in my search for help with the situation of grandparent alienation. They have many resources and tools for help.
Some of my favorite tools are the scheduled support meetings throughout the entire country both in person and via telephone. These meetings create a safe place to share our stories with others in similar situations. It has been extremely comforting to be in touch with other people experiencing alienation in their families, as they truly understand and are very compassionate.
I would highly recommend checking out their website and browsing through the large variety of postings and references. There are 105 support groups in 50 states and 21 countries. May you find comfort on your journey.
Grandparent Alienation Forum 