When is enough...enough?

My mom is 85 has been in the nursing home for 18 months now. She broke her hip in March and has steady gone done hill mentally since then. I went to see her today, I go everyday during the week and take weekends off. She was in her room today with her door shut a little. I walked in she was in her wheelchair and her dress was all bunched up. I said let me fix your dress she said its wet..I told her ok then we will change it. I lifted it up over her head and she didn't have a pull-up on. I said where are your pants she said I went to the bathroom and I couldn't find them. She was just fine without her pants on...it broke my heart. My mother has always been a very proud woman. Matter of a fact, she takes herself to the bathroom and I told them that they would never be able to stop her from doing it unless they tie her to the chair and I don't want that. I got an aide to help me get her pants on. Her mind is just fading fast since she broke her hip and I am just lost. The head nurse talked to me and she said to be thankful that my mom isn't aware of her surroundings or bothered by not having her pants on She is going to make sure the CNA's watch her closer because they have been so accustomed to her independence...they are going to check her for a UTI but I don't believe she has one. I do not want any extreme measures taken with my mom. I don't want her to end up being a rag in a chair. I am an only child I am the only person who sees her that doesn't get paid to. I hate this so much. I am just at a lost. She is becoming more and more reclusive and happy to be so. My instinct is to fix her but I know she is content. I think conversation causes her to get upset because she does not comprehend like she use to. Her roommate is comatose and tube-fed and my mom loves hers. She says that she talks to her. Her roommate requires nothing from her...this is by far one of the hardest things I have ever gone through. My dad died suddenly when I was 22 that was hard but NOTHING like this. She was under hospice care but they stopped it not because she was better but because she had not gotten any worse. She felt thrown away and it just messed her up that her routine changed that was probably 8 months ago. The broken hip started a downward spiral and in 4 months she is a different person. Mentally, she has been delusional for years, but she remembered things and could carry on conversation. I am rambling now, but today at this moment I am just lost, hurt, scared and just want to run away from it all...When I told the nurse today if she had a UTI just leave it alone I didn't mean it I called them back and said if she does to treat it I don't want her uncomfortable...but I really do not believe she had one . Her urine doesn't smell strong etc... also she has stopped eating, they are giving her ensure but she has not appetite.