I implore all grandparents to take a good look at their relationships with their grandchildren and to try to strengthen them – whatever the emotional and physical costs. Grandparents have a special role, as they are generally not burdened by the day-to-day raising of their grandchildren and thus are able to give them undivided attention and love. Grandparents sometimes don’t realize how their love can affect their grandchildren in a positive manner.
The jealousy that a mother-in-law may have toward her daughter-in-law for taking away her son and then successfully creating a beautiful family with him may be an underlying cause for her behavior. This is surely not a rational way to feel, but jealousy is not a rational feeling. Your techniques will likely be effective if this is the case. So if you continue to show kindness and love to someone, the recipient will hopefully be able to eventually overcome his or her jealousy and return those feelings.
Thank you again for sharing your experience and helpful advice. Hatzlachah!