Thanks, you are right about there being so many subspecies. I did not see any with the thick, fleshy leaves like my SIL's plant but the flower is a dead give away now that I see the others and in many cases the leaves were not shown.
Great pictures! It closely resembles what is called a Streptacarpella Streptocarpus saxorum on Google. Some of the pictures here on PlantFiles do not look similar but there are probably many varieations.
Streptocarpus saxorum, or at least some of it genes, seems likely since it is a widely grown plant that has been around for a long time. You'll have much fun growing it. Easy to propagate by cuttings and a nice subject for a basket. They can have a spectacular flush of flowers.
Streptocarpus is divided into two subgenera: subgenus Streptocarpella contains all the bushy, upright plants and subgenus Streptocarpus contains all the "typical" Streps aka. "Cape Primroses".
To make matters even worse, Saintpaulia (African Violets) are the closest relatives of the subgenus Streptocarpella and thus an inclusion of Saintpaulia into Streptocarpus presumably as a third subgenus has been proposed.