My Xillia was a JRT/Chi/Dachshund mix. She was REALLY smart and the most facially expressive dog I've ever seen! And her eyes...just thinking about them get to me. Big expressive eyes.
Xillia was also a rescue (she showed up on our driveway one night and never left lol) and was definitely abused. She would run when we would get out pots and pans, poor thing. But she was the biggest cuddle bug!
Did you make a decision yet? I'd say if you have the means and time, take her in. Your friend will still be able to visit and see him.