Hi, I'd like to help you with your question.
It sounds like your cousin may be grieving. In grief, people can express themselves in different ways. Grief has five stages, which include:
Denial- happens when we first learn of a loss. The feelings are so overwhelming that we block them out to protect ourselves emotionally until we have time to adjust.
Anger (the stage your cousin is in)- occurs when we being to realize what has happened. The feelings are overwhelming and hard to cope with so we turn them around and try to find an outside source to blame. It can be the doctor who told us our loved one died or a relative or friend. We blame so we can deal with a loss that has no explanation. We try to find a source that can be faulted so we have something to focus on.
Bargaining- when we feel vulnerable from our loss, we try to find ways to gain control again. We do this by trying to bargain our way out of the loss. Making deals with God, saying you'll be good so the situation will change. These things are ways to try to make the loss seemingly in our control
Depression- any loss can cause depression. Sadness, crying, loss of appetite, and trouble sleeping are common. This is when we begin to accept the loss and the reality of it hits us. The danger is when we feel so bad we want to hurt ourselves. Then professional help is needed.
Acceptance- this is when we are able to accept the loss and we start to deal with it. It is not about being happy about the loss, but more an accepting and calmness about it.
Your cousin is in the anger phase. She is looking for ways to blame others and she is becoming destructive. Has anyone tried to confront her? Acknowledging her pain and recognizing that she needs to face it is something she needs to be told. Is she willing to get help? A good start would be for her to see her doctor. Medications can help her feel calmer and give her a chance to get help.
Does she attend church? Maybe her pastor could talk with her. And someone can also talk with her daughter. She needs to know that her mom is not doing well and that what she is doing is not right. The family can offer support to her by offering to take her for a few days at a time to give her a break. She may be grieving as well and not be sure how to handle this.
Counseling is the best idea for your cousin. She needs to talk out her anger and grief. If she is willing, have her see someone. Here is a link to find a therapist:
Support groups also help a lot. If she can talk with others who have got through the same experience, then she can start to heal.
Also, the family can resist her actions. Don't allow her to act out. When she does, leave the room. As long as she feels free to hit and lash out, then she will continue. Tell her that she is not allowed to hurt anyone else.
Understanding your cousin's grief would help. By understanding what she may be experiencing, the family can approach her in different ways to see what works. Here are some resources to get you started:
On Grief and Grieving: Finding the Meaning of Grief Through the Five Stages of Loss by Elisabeth Kubler-Ross and David Kessler
Getting to the Other Side of Grief: Overcoming the Loss of a Spouse by Susan J. Zonnebelt-Smeenge
Awakening from Grief: Finding the Way Back to Joy by John E. Welshons and Dr. Wayne Dyer
You can find these books on Amazon.com or your local library may have them for you.
Let me know if I can help any further,