Like @Fred Hellermentioned it sounds like this is a disability guided request....So what does the ADA say about "reasonable accommodation"?

What your tenant is speaking of falls within the following;Emotional support animals, comfort animals, and therapy dogs are not service animals under Title II and Title III of the ADA.

Long story short she put a house on Craigslist for rent and then noticed a rogue ad a week or two later with different contact info--offering to rent her house at a different price. 

If you want to make their life easier, offer to replace the toilet with one that is chair height (also known as high boy or ADA compliant).

Title Company We recommend TitleOne in Ada/Canyon County with extended coverage5.

I suppose you know what the balloon payment is now, however most residential loans are NOT assumable and I read the ad as the seller selling as a "Subject-To" transaction as an all inclusive deed is a type of special warranty deed where the seller does not give clear title, title is subject to paying off the existing lien as agreed.

Fred Heller This is Ada. 

Though both Fair Housing, and ADA protect the disabled and an arguement could be made that an obese person is a disabled person.

I find that I get 33% more responses when I run my ad as "rent to own, free credit repair"  of course the credit repair is not free, my tenant buyers pay for it with the NROC "non refundable option consideration payment.  

Many capital improvements recently made to the property including new paved roads, Welcome Center with laundromat, and ADA compliant bathrooms.