Hi chimera. I am so sorry for the loss you feel. It must be so challenging. Anger is one stage of grieving.
The 5 Stages of Loss and Grief | Psych Central
One way out of this series of reactions is to have a therapist that specializes in coping with grief to help you move towards a reconciliation with the loss of your dad and the anger towards your mom.
If for any reason this is not possible then you may find these articles a place to start.
On Grief, Loss and Coping | Psych Central
Grief and Loss | Psych Central
You may also find these support groups are a way to move through the stages of grief.
Grief and Loss: Support Groups | Psych Central
Please feel free to private message me or any of the Community Liaisons by left clicking on the name in blue to the left of their post) for questions or just to share.