The Blame Game

The quickest way not to get anywhere productive, is playing the blame game. It may be one nurse blaming another, or "it was an agency person", or "it was the other shift". Give me a staff person any day, who looks you straight in the eye and says "I'm so sorry. What can we do, to make things better?".
So instead of looking for the culprit responsible for whatever has raised your ire, which accomplishes little, let the nursing (or housekeeping, or maintenance, or whomever) take their own internal measures by :
A) Making sure the right person knows there is a problem. How do you know who the right person is? When in doubt, tell the Unit Manager (or Nursing Supervisor). Not to worry - if another department goofed, they know who to refer it to.
B) Let them know exactly what (when, etc.) the problem is, why it is a problem, etc.
C) Now, at this point, it is not out of line to ask "what are you going to do, to make sure it doesn't happen again?"
D) A telephone call the next weekday to the person in charge (of the unit, or the facility) is not only a good thing, but, will make sure you get follow-up.
What can I tell you won't (and shouldn't) happen. One staff member should not identify another staff member or shift as "responsible". Disciplinary actions should not be discussed with you.
What should be? The problem should be clearly identified. The corrective action should be in place. The appropriate staff/discipline should know what is expected of them.
Who is responsible to make sure that happens? The person in authority who you went to in the first place, their boss, and various other levels of the power structure. Social Services (the Social Worker) and Nursing (the Unit Manager, Supervisor) should be involved.
What does the blame game (yelling, etc.) accomplish? Usually very little other than people not hearing your message, only your noise. They won't think you are more involved, more supportive, or more loving.
Being polite, firm and tenacious always works.
Your family member deserves good care.