Kiki has been accused of being a yorkiepoo too
, but not since she was a puppy.
It's probably the texture of her coat that makes people ask that, more than the color. In the pics, it looks like her coat is possibly a wavy, "cotton" coat, rather than the standard straight silky yorkie coat.
How old is the doggie?
She looks like possibly not the best QUALITY yorkie (or maybe those aren't the best pics!), but I think your mom can rest easy that she does have a yorkie. We've all seen many with coats that color/texture.
Here is Kiki....she is several months older now, and is even more light colored around her face: