It is very difficult to see a loved one change their patterns of behavior as Alzheimer's disease progresses. Good hygiene is important to health and it is important that some minimal standards are maintained so that she does not start getting infections or sores.
You also have to, perhaps, accept that her levels of distress will sometimes override the need to change her clothes or have a wash before she goes to bed. If someone refuses you can try a few different things. For example:
Try asking her again later. She may be less agitated in the morning than in the evening.
See if she is more cooperative if she is assisted by a woman, (maybe your partner could try to help).
Does she like to shower or take a bath, go swimming? A change of clothes can be given afterwards.
Music, food snacks as rewards may help make her be calmer during her wash/clothes change.
Presumably she does change her clothes and wash sometimes with your father's help. What does your father think? Is he resistive to your ideas of hygiene or does he just not want others taking over his role? It can be very hard for some people to have strangers, professional caregivers, in their home helping out.
If she is agitated all the time then it maybe would be helpful to get a doctor to evaluate health risks and think of some mild sedative medication. However if you are not there on a regular basis and your father does not see the need for medical help you do have a problem.
Maybe you just have to accept the situation unless you feel your mother is at risk through neglect.