I am in a good situation, financially, to be able to entertain buying a cabin in Sevierville! 

I know my personal risk tolerance and financial limitations (high school teacher for most of my adult career), so I insist on enough cash flow to grease the wheels in case of tough times. 

Early on in the pandemic when we had our adult children living with us, whenever anyone was exposed to COVID our expectation was that the exposed person used one bathroom during a quasi-quarantine period while everyone else used other bathrooms in the home. 

The most painful part of the process is moving as an adult.

The HOA said I would be fined if any more complaints are issued.This is obviously an issue for the other tenants, but mine is a man and his adult special needs son.

We have run into this several times and have reached out to the emergency contacts, generally an adult child. 

Run separate background/credit/rental history on each, and that comes at a separate cost for each...Remember, one applicant may be glowing, while the other is trouble, so you want to check everyone.Everyone 18 and older is an applicant and will be on the lease, so add any adult kids to that process and collect those fees as well.

So I would encourage you to talk with your adult family members and find one who wants to create an LLC with you to buy real estate.  

4 Unrelated adults in a single family home. 

In my opinion the ONLY way you do that is by treating him like an adult and simply being up front and honest, and say "I'm not renewing your lease so here is a 30 day notice to vacate".Avoiding difficult situations isn't going to make you or him better off.