I have worked in nursing homes, retirement homes, hospice, and as one of the attendants that you're speaking of, so I know what it's like for you. Sometimes, it's the caregivers that are in need, psychologically and physically.

When his daughter comes to visit, then that is your time off (I use the word "off" knowing that you want to be there and it's not an obligation for you..).

She doesn't get to be "entertained". She is there to visit her father. And I think it would be a really good idea for family to have first hand knowledge of your s/o's condition.

Perhaps you're looking forward to these few days, but I am of the opinion that you're doing yourself and your s/o a disservice if you don't stay out of the picture.

You can claim an illness, or tell the truth, or go away yourself for a few days (even stay in a local motel). And, even if it bothers you to do so (and I get the impression that it will), be strong and leave them both to it.

Just my opinion.