A Chinese article from 23-02-2016 describes the life of Lee Heung Kam, the article also mentions Barbara (article about lee Heung Kam)
Note from the translator.
"Nominal family relationship" is a Chinese cultural custom. It is similar as blood relationship (http://en.wikipedia.org/wiki/Blood_brother) but also has its own meaning.
1. The persons involved in are in different generations. (Because in different generations, it is not good to call sister or brother to each other.)
2. Extremely good personal relationship.
The reason why Lee Heung Kam was chosen was that she had a really good personal relationship with Barbara and as a coincidence they acted mother and daughter in teleplay "United We Stand". Barbara said Lee Heung Kam took care of her a lot when working together for "United We Stand". Lee Heung Kam also gave her a red envelope on Barbara's birthday.