I'm not sure how different it is for housing, but in the workplace employees can not only ask what your need for an ADA work place accommodation or leave, but give you forms that your health care providerwould need to fill out.

Even after that they can still refuse your accommodation if it places too much "pressure" on the business needs both financially and in terms of effectiveness. This of course is subjective, but could become a compliance (legal) or liability issue if a company isn't careful.

If you want to know message me. I work in this field, but aren't big on giving details away about my employer in this day and age.