i would suggest you get a further diagnosis.
a person can have dementia but can also have a mental illness, such as a psychosis or paranoid illness, or can be acting out PTSD issues (common both those who have served in wars and in those sexually abused as children).
continual and wild aggressive behavior, emotional turmoil at night and making plans to kill people is NOT a sign of dementia, especially since people with dementia are brain-incapable of making logical memory-based plans.
there is something else also going on here, and a more accurate oir additional diagnosis will help get truly helpful medication that may bring peace to very troubled minds.
unfortunately, in our current medical thinking, we have demonized dementia illnesses so much that people with dementia are assumed to be capable of any degree of crazed behavior but it's just not so.
i've worked with dementia for over 20 years and these extreme violence situations are connected to mental illness issues. and, yes, a person could have a double diagnosis, it's true -- dementia AND mental illness.
sometimes, it can actually also or instead be linked to adverse response to medication issues. either way, to get the help needed to be able to make the best care decisions, further diagnosis is needed here. that way, perhaps everyone can get help so future care needs can be more accurately designed.
psychiatric examination and medication review is a good start for figuring out what's going on here. do try for that. it will be worth it. get a referral from the doctor and follow it through. it's all cpovered by medicare or VA benefits.