I second Sherefe

I know some mothers are abusers themselves. I am referring to those who are not:

http://www.mosac.net/

“What mothers feel:

Initial Reactions in Mothers

The response of a mother to the disclosure that her child has been sexually abused is different for all mothers. The grief reaction of the mother varies depending on such factors as her relationship with the child, relationship with the perpetrator, available coping skills, level of belief in the disclosure, life stress, and anxiety level. Grief reactions, mourning process, and grief tasks are similar to that of the victim. Responses to the disclosure of sexual abuse include:

Shock. This is a normal human response to unexpected, painful events.

Denial. Denial is also a normal human response that occurs in the short-term following the shock of painful news. However, denial is not healthy if it cannot be overcome fairly quickly.

Acceptance of the reality of the abuse is the only way that the mother can provide support and protection to the child.

Anger. Anger is also a normal human response to shock, pain, and betrayal. However, if not managed, anger can become a destructive force that impedes healthy communication and processing and consumes the energy of the mother. It can either focus the mother on protective action or defocus her from the immediacy of her role. Anger management skills are crucial during recovery from the shock of discovering your child has been sexually abused.

Guilt. Guilt is also a normal maternal response to disclosure of sexual abuse.

Depression. Depression will occur if the pain, sadness, guilt, and other negative emotions are not addressed and managed. Depression is debilitating and will interfere in effective function as a mother.

Fear and anxiety. Fear is the normal response to threat. Anxiety is the normal response to the unknown. Mothers face a life-altering threat with no knowledge of the outcome.

Acceptance. Acceptance is the final stage of a grief process and, in effect, entails facing reality.

Confusion - Confusion is a response common to any event out of the ordinary. We try to make sense of it and have conflicting thoughts and feelings.

Mothers may also develop posttraumatic stress disorder, PTSD, and have anxiety and panic attacks associated to their child's abuse. “

I have been through most of these stages. I was depressed, I get depressed, I haven't gotten over anger. I have PTSD. I am still in shock after knowing for 10 months. But I keep my feelings at bay because I do not have time to waste, I have to fight with all my energy to minimize or undo what was done for my son.

Please be gentle to your mothers. You don't know what they are really going through. They'll probably take a long time to fully understand what happened and the consequences, on you and on her.
The forum with mothers of sexually abused children is full of severely traumatized mothers, taking medication, and going spiraling downhill trying to deal with the abuse. At the same time, they keep the appearance that everything is fine, so that their children do not get even more traumatized.