I can't help you with a particular recommendation, since I don't personally know these dogs, the breeder or your area. However, ask to see the therapy dog certification. There is a gentleman in my area that breeds Labs and advertises the parent dogs as "therapy dogs". But they have never been certified. He brings them to visit his elderly father in a private assisted living facility. That is it. I am not sure I would consider them "therapy dogs", at least not as I understand the term.
A certified (or non-certified, for that matter) therapy dog isn't necessarily going to produce service dog candidate puppies. If your goal is a service dog, look at organizations that breed and/or train and place dogs that perform the duty you need.
There is a whole section of this BB that covers service dogs. You might want to post this in that forum. It is titled "Guide, Therapy & Service Dogs" and is down the forum list a ways. You'll get responses from experts, which is always a good thing!