How can I visit my aunt in a nursing home without crying?

My aunt is in a nursing home with cancer and does not have long to live. My mother goes to see her several times a week and wants me to go. I have a hard time going to see her in the condition she is in. All I do when I go there is cry. I don't want my aunt to see me this way considering it is not helpful to her declining condition and I want to try and keep a positive attitude for her.

I don't like the care she receives in the nursing home either. If I were her daughter I would have rather had her stay at home with hospice, but she has already taken over her mother's house and converted her bedroom.

My aunt is lonely and in pain. I can't see her like that because it hurts too much. I have tried to explain this to my mother and she doesn't seem to understand. I want to see her but how do I keep from crying and deal with this before and after? And how do I deal with the emotions of anger at how the nursing home and her own daughter are treating her?