I don't know if this is the right forum to ask this question, this is my first posting here so please bear with me.

Can a person download from limewire to a mp3 in mono? The reason is a person I know can't hear out of one ear. So if you download in stereo and listen with the earphone plugs she is missing some of the music.

Most files will be in stereo .. and are what people like yourself are sharing.
I'd suggest you set your computer settings or headphones to mono setting.
Other alternative is to convert to a wav file & convert it to mono when doing so. Audacity (click on link is a good program that can do that, but then, most audio players can convert to wav & with luck to mono also .. check the conversion options.