<human>: Can you summarize the given text in a few sentences?

I'm on mobile, so I apologize if this doesn't end up in the Non-Romantic category. 

My sister is a very reserved person. She keeps quiet until you really strike a sensitive spot. Her previous boyfriend was physically and emotionally abusive, but my parents don't really know. My mom knows she was emotionally abused, but that's about it. 
Because of this, she doesn't like being touched so much and she doesn't like people too close to her. I don't know if this has anything to do with it, but she can't sleep in the same room as other people. She refuses to fall asleep in front of us, so I doubt she lets anyone in her bedroom. 

My mom is aware of this, but our aunt is in town now. Our Aunt has a fear of sleeping along. So we've got a sister with the fear of sleeping with people, and an aunt with the fear of sleeping without anyone. My mom then asked my sister if she'll let my aunt sleep with her. 

My sister said, "She can sleep on my extra mattress, but I don't feel comfortable if anyone is in my bed. She'll be next to me in a sense, but I don't want anyone in my bed with me."
Mom got angry and said that she needs to let her sleep in the bed. But my sister kept saying she's uncomfortable. I know this because they were arguing right in front of me, and trying to get me involved. 

She keeps asking me for advice, because she feels really guilty. But I believe my sister when she says she won't be able to sleep. My aunt might not even be 100% afraid, my mom could be exaggerating. What do you guys think?  Is it acceptable to force my sister to be uncomfortable for the sake of my aunt being lonely?  I feel like this is really tricky. Please give your thoughts.
<bot>: My sister has expressed her discomfort in sleeping with someone in her bed, but my mom is disregarding because my aunt is lonely and likes to sleep in the same bed as other people.