Seeking a future Service Dog (San Tan Valley)

For the last two weeks of hospital stays and realizing that what we’ve been doing to help my wife simply hasn’t been enough.
We have been encouraged to look for a service dog candidate.
What will the dog’s tasks be? Asthmatic and heart rate alert with the ability to distract and calm.
This will be in addition to some psychiatric tasks but the primary is heart rate and asthma flare alerts.
What we are looking for? Medium size, calm nature who gets along with everyone and everything - cats, loud noises, everything (this is super important!).
Neutered/spayed a plus with vaccines already completed.
Must be potty trained.
Small rehoming fee would be appreciated.
Would prefer older 2+.
Would not be able to go down to the shelter as it would only cause a flare so this is the next best option in our search.
Thank you