Relative diagnosed with Alzheimers

P roblem. "Joan", relative,widow,
lives alone. Recently diagnosed with Alzheimers. SS have become involved. SW has said that the family should persuade her that she needs a cleaner to come in once a week for a couple of hours re cleaning and safe food storage.
Joan very resistant to this. SW has said that if we fail to persuade her she will.have to force her to.do it.
My question is, how would she do this? I.would like to know so.that I can.tell Joan what would happen if she did not agree to.it. All.done by phone as we are not at all.local.