Thank you for making me visualize the gory possible outcomes of renting to someone like this. 

You can tell the OP he got the best possible treatment in the best of all worlds all day long, doesn't change that.

They can probably do a visual inspection immediately and indicate whether it is likely or unlikely, then they can conduct a physical test of mold in the air and on surfaces.

If someone is so "disabled" they can't live in the privacy of their own home without the presence of a dog or cat, that indicates they are in need of regular, on-going treatment.

Adding a camera allows for visual of activity as well.

Jumped onto my trusty 3d software for a quick visual.

It is hard for almost all of us to look past the visual.

It was a miserable experience for me, as a result of his disorder he really believed that he was entitled to all types of special treatment.

If the tenant has a legitimate issue I would try to work with them as much as I reasonably could, but they would need to provide me with documentation from their treatment provider that they are receiving mental health services - they do not need to tell you all the details just validate the issue.

Do you mean for substance abuse treatment?