My foster daughter is driving me bonkers

A foster child might have some serious issues with rejecting or abandoning a dog like that. You could get a dog trainer to help you and your FD with the dog. Or find a training class your FD could enroll in and take responsibility for training the dog herself. There are a lot of different breeds that are being used as mental health assistance dogs but many people just get their pets trained so they can take them with them everywhere they go.