This is not the place to find that kind of help..but maybe someone on the forum knows an agency that can help. you.
I think it would be advisable to contact a reputed agency, organization, etc in your own area. I would also check references, qualifications and experience, etc.
I also find it offensive when you mention Alzheimer personality.
I know you're just trying to find the best support for your mother while you're away (probably on a very deserved break) but I perceived that as being quite negative. It sounds like you mother may be fiercely independent.
Good luck for finding appropriate cover and enjoy your three weeks.
J