Screening Disabled Applicant?

[Josh L.]

Since people with disabilities are a protected class, how do you go about screening them and what type of questions can you ask without breaking any laws? 

The applicant is disabled so there's no job or paycheck, but applicant gets a sizable disability check and social security benefits. The disability check and social security add up to 3X rent. 

But, I'm concerned about the disability check. I want a one year lease, but how do I know if the disability check will be a steady income for a year? Or, is it once you're on disability, you'll get it for the rest of your life? Without the disability money, the applicant won't be able to pay the rent just from social security. 

The applicant isn't even 60 yet, but is already receiving social security? Applicant showed me a copy of a letter form social security about current social security benefits. Is applicant already social security because of the disability?

When I check references with previous landlords, can I ask them what reasonable modifications or accommodations did they need to make for this disabled applicant? 

Is there anything else I need to know or should be concerned about with renting to a disabled person?