aunt

no ihaven't suggestion

just say "we" need to clean up cause there is just so much to do or something like that. you know what i mean?

What exactly do you mean by "clean herself up"? Shower?

Perhaps instead of telling her you can do other things to make it easier for her. Like maybe putting extra bins in rooms, or tidying up after her while she is still there so that she will get the hint...

Be completely honest with her before she arrives. Let her know that you appreciate her coming to see your mom, however, you have your hands full looking after her and cannot dedicate time to serving her, making her bed, etc. If your aunt is told ahead of time, it will give her time to think about it and realize that she's been selfish expecting you to do everything for her as well as care for your terminally ill mom. Best of luck!