The idea with your zoning currently is to allow only 1 dwelling unit per 5000 sq ft, with the few exceptions that Brian mentioned above, and with all of the proper setbacks. 

That he wants to spend the rest of his life, however long that may be, as a human being. 

Hey Eric,  I would suggest getting a quote to add the rental as a second location on your existing home insurance policy (be sure to disclose that this home is a rented dwelling).   

The cost of an appraisal may not even be necessary as automated valuation models do not involve a human inspection of the property.

If I were to acquire the property, what would I have do to make this a legitimate (and safe) dwelling without putting myself at risk?

Except for these added costs, companies also run the risk of human errors, which can only make the reconciliation process more costly and hurt investors’ returns. 

This is human nature.

This approach tends to appeal to computer programmers, a new segment of the freshly affluent in our society who have made plenty of money out of math and are already half-deluded by their success in computers into believing that equations applied to concrete, earth, wood, steel, human failings, weather, and the inexorable passage of time will yield a golden system that anyone can use to become fabulously wealthy out of land and the structures built on it.Regard the mathletes and their beliefs with a healthy dose of skepticism, drill down past all the fascination to what these numbers are supposed to offer you in the way of insight, and you'll be fine.

; ) Never underestimate the power of dreams and the influence of the human spirit.

I have long held the belief that we as landlords have the opportunity to do good for humanity and good for our community.