Dementia in 82 yr old mom Please help me and my sis how do we cont to cope?

trying to keep her out a nursing home but she has sundowners and gets very violent esp at night she is a good christain woman but turns into the devil at night and it takes nothing to set her off.My sis has gotten so distraught she me last night she hopes Mom dies in her sleep and does to heaven as we know she will as she has said "I belong to 'God"