Are their caregivers that can take care of parents with dementia?

Yes, there are! Many different companies have caregivers with different skills. Some are trained specifically with dementia and Alzheimer's.

Yes, in-home caregivers take care of people with dementia but taking care of 2 people at the same time, both with dementia and other illnesses may require another kind of set up. Call a nursing agency that staffs caregivers and ask their opinion. I'm a home healthcare nurse and I would not accept a job of caring for 2 people with dementia until I knew how severe each dementia was. Can I turn my back and help one person and leave the other person unattended? Will one person get upset if I'm assisting the other person? How long are the shifts? Can the needs of both be met by just one person? There would be many variables to consider.