Welcome to YT. Am so glad you could join even if your daughter is the one who has the Yorkie.

Their are some coat differences in the Yorkie and I've found what works for one may not work the same for the other. I bought many brands trying to get one that works on all of mine and found #1 All Systems shampoo and conditioner is the best.
#1 All Systems - Complete Line of Grooming Products
I use the Super Cleaning & Conditioning Shampoo and the Botanical Conditioner.