Abandoned Kitty

My friend's neighbor just kicked out her boyfriend and then let his indoor cat out to fend for herself. This cat has only ever lived inside and is scared to death. My friend is feeding her and trying to keep an eye on her, but there are a lot of territorial street-wise stray cats out there looking like they want to fight so my friend is terrified for her. She is small and not exactly well-fed, but looks healthy. She's probably spayed but my friend honestly has no idea what her history is. My friend would try to find out but she's afraid she'd wallop her neighbor if she even spoke to her about the poor kitty, so my friend is keeping her distance.