Are multiple personalities normal with dementia?

My children are kept separate from her most the time. Only there here and there as we live right next door to her. My adult child does live with her whom is a registered CNA. Anytime she has became combative we have quickly removed my younger children from the area, but they have still caught bits and pieces but never her physical attacks. However I have caught great grief from my sister and other family members for not moving in with my mother, I completely refused to for my children's safety. Please don't think I am putting my children through her physical attacks. They have seen once when she was fighting with someone in her head and speaking in two different voices and that was it for me and I would not allow them to be around her much. We go there as a family to have dinners ect with my mom but my husband and I work very hard to keep them separate. They do get scared while eating and she all the sudden starts talking and arguing about not liking the food. I quickly intervene when my children are present. When they saw the attack by my mother, I had her immediately hospitalized. And then was called worthless and told I did not love my mother because I would not move my family in with her by my sister (whom may I add, lives in another state and for the last two years has not seen my mother) and by my mother's friend. I would not bring my mother home until she was no longer physical. I also removed my mother's pets from her home which was frowned upon by others. But I had to protect them. I live a 1 minute walk next to my mother, yelling distance as we say and I told my sister that was going to have to be close enough for my children's sake. My 'homes' stay very divided with me being with my mother and adult daughter or my husband being there. We do what we have to to protect my younger children.

The doctor just keeps telling me that this is 'normal behavior' even when he has seen video of her sitting straight up in bed screaming and yelling. My oldest daughter has worked in several nursing homes and never seen behavior to the extreme my mom has taken it. I'm at a loss on what else to do. And thought I would try here for others that possibly have seen the same behavior with dementia before looking for another doctor's opinion.

She is on meds for dementia as well as hallucinations. She has been very combative before including throwing things at us, came at me with scissors, hitting, ect. Now she is screaming and yelling "we will kill them all" at the top of her lungs. She argues with us, throws food, has thrown her poo. I would be ok with happy hallucinations but she is extremely angry all the time. Its angry or crying. No in between. We have tried different psych meds which seemed to make things worse.