My tenant mix is broken up between long term(like 10yr and 20yr long term) elderly tenants who are on a fixed income and want a quality place to live, and shorter term young professionals who typically stay between 6months and 24 months. 

I have seen other people renting it to medical professional who are staying for residency or moved in the town for jobs and stay until they settle down with a house, or elderly people who are looking to retire in an apartment and don't care about maintaining a house.

I would also call the police to do a wellness check on the tenant (especially if they're elderly) and make them aware of the crying dog.

Look for a SRES or go to sites specializing in elder care.Want a Realtor with a specialty in short sales? 

The seller was elderly and not business savvy (she ended up passing away before closing), so the sf was listed as "buyer will verify".  

I'm thinking primarily of elderly homeowners with dementia or simply overwhelmed with life. 

I have some elderly neighbors. 

The example they talk about in real estate license classes to explain this is, suppose an elderly woman wanted to rent her own place but was afraid of potential confrontation with young men, she could choose to rent only to young women to satisfy her safety concerns.I hope this helps! 

For example, an elderly couple might be willing to pay more because they feel that the "quality of cash flow" (consistency) is more predictable.

The lady was elderly and old in age with medical issues and felt all the cats were her friends even though she could not care the right way for all of them.