While living in an assisted living/memory care residence, my Mother developed a kidney infection, resulting in hospitalization. Upon examination the doctor suggested neglected hygiene care by her care givers. What are the recommended steps to amend the neglectful care? Plus steps to file complaints with: the facility, county & state of Wisconsin, agencies.
Let them be part of the team and the solution. That will require them to do their own investigation and problem solving, and they shouldn't feel threatened.
Another thing to ask in their consideration is "how can WE ensure this doesn't happen again", or less threatening, "how can we avoid this from happening again"?
Think of ways you can help your mother, such as suggesting to the agency that they make hygiene a happy event, followed by tea, cider, listening to music, something that she looks forward to after the bathing, cleanup or similar activity.
I would contact AL admins in a neutral, non accusatory way and tell them the findings.