Don't stop praying for your family; God is stronger than even the most stubborn heart, and He is able to overcome even the greatest bitterness and anger. The Bible says, "The prayer of a righteous man (or woman) is powerful and effective" (James 5:16).
Keep trying also to bridge the gap between you and those in your family who have turned against you. Let them know that you care for them, and you don't want this conflict to continue for the rest of your lives. If you can, ask one of them privately what they think you can do to reach out to those who have turned against you. The Bible says, "Make every effort to live in peace with all men and to be holy" (Hebrews 12:14).
At the same time, you may have to face the fact that this situation might not change anytime soon. Things like this have a way of getting out of hand, and the original reasons for the conflict fade into the background. Pride, anger, greed, resentment, hurt feelings these easily take control and overwhelm the original issue.
Make sure none of this happens to you, but make it your goal to live for Christ, and to put Him first in all you do.