Good recommendation though -- just need to look for the Westie breed club.
This is not the breeder I would pick for the reasons indicated. I am not familiar with the standards of all these dogs this breeder breeds so can't comment on how they look but still ..... when multiple breeds are being bred, and mixes are being sold, it sends too many red flags for me. I do not like when they actually put a price tag online and sell without even wanting to meet with the buyer to see what kind of home they will provide. I do know a breeder that sells online but still is very selective when people answer her website. They have to fill out an application and go through a phone interview if they live far, otherwise she sets a time to meet. That is the kind of care you want them to have. If they are particular about who gets their puppies, they are more likely to have taken care with them.
Remember a westie has a double coat and sheds. They are cute though. Here is a link that gives info about looking for a good westie breeder:
Westie Breeder Referral for Canada and the US
Thta is very kind of you to agree to let your mom have your Yorkie. I know they are easy to become attached to and would be very hard to give one up after caring for them. It will probably be easier on Emmett too. You will always get to visit with him but have a new puppy to watch grow up too.