Just don’t think that because of your related, but not direct, experience your project is a slam dunk.

I think you will find your relative costs for prime real estate will make the venture unprofitable, but perhaps you can locate a property with an ADU or a run down old cabin in which you can experiment. 

What is you had a relative living in a park like ours and a big corporation took over and jacked up lot rents so high that your relative or even a friend was forced to go elsewhere.

You are too trusting and while your relatives may mean well, but who will pay for their mistaken info?

But unlike your relative she loves her job so maybe that is why she was tagged. 

If you adhere strictly to the laws, you will be limited in the services you can offer to your relative compared to what they would get if they listed their property with a licensed agent, and they will get less money for their property working with you than if they hired an agent.

While I understand you want to buy the house, you are at the mercy of those that your relative sold the property to.  

The executor of the estate also should have had some basis for that as well.Fair market value when your relative passe as @Jake Baker and @Cory Carlson said.

Your relative is not a tenant screening service and you should not accept tenant placements from people you know.

If you want to run a charity for your relative, then you could just help them with the mortgage, or buy the house from them for a great rate and let them live there cheaply.