getting more mice

My Eminem died last night. He wasn't right to begin with. We had paired him
originally with a female (for those of you who remember about 3 months ago
Sid was a *very* dominant female and once we gave Sid a new home with other
females she seemed to be happier) and Eminem never mated with Sid. By the
time we separated the two mice, Sid was bigger than Eminem. After a few
months with his new female companion Eminem finally grew like a male mouse
should, but never mated with the other female. Now this newer female is the
one who had eye problems, and right before Eminem died she had ear problems.
Eminem chewed her ear off. It was then determined that the female mouse has
a tumor on the left side of her brain which is causing the blood supply to
be cut off to her eye and ear, hence her losing both. What should I do with
this mouse? She doesn't seem to be in any pain, but she is living alone and
I don't like that. She is a very petite mouse and was never dominant (even
to the ever submissive Eminem or her other female friends) so I'm thinking
of getting some new female mice. Or, with the bad experience I've had with
Eminem, I might just put the other mouse to sleep. What is your opinion?
Should I let her live out her days alone, have her put to sleep, or should I
introduce some new female mice to her? Or is there another option I'm not
seeing here?

Bethany