Sometimes the condition is caused by medications, especially if someone uses lots of different ones. In such cases taking them off the meds may help their mental awareness, but caregivers and medical professionals must weigh the benefit of that against problems caused by stopping meds that may be for life threatening conditions.
I've heard that music, especially the kind played at emotionally important times in their past like Christmas can help the patients, although it is only temporary and certainly not a cure.
Someone who worked in a nursing home once told me when people with dementia start acting mean or angry they're likely to start wandering, too. In nursing homes bracelets set off alarms when people wearing them try to leave the unit. Perhaps motion detectors might help alert home caregivers.
If someone with that condition lives at home, the family caregivers have little or no freedom, even with part-time care by others.
The hardest part of dealing with dementia is that the person who has it is gradually lost to their loved ones, who must live with constant grief until the closure of death.