This, the same as any other business, comes directly from revenue which ultimately comes from you the client. 

I no longer qualified for traditional financing because I already own many rental properties and my DTI was high for the bank, so I purchased these in a business entity with a trusted private investor and was able to refi the 1st property/sell the 2nd property to pay back my investor and ultimately keep the better property for zero money down.

With your development idea, start the discussion with a lender since they will have ultimate control.

Ultimately he is responsible for his own safety so long as you are providing a safe dwelling; however, if he is endangering others you have a couple remedies as I see it.

@Joseph MuleroTo boost your rent plan and make more money in the medium-length rent market, think about these steps: slowly add furniture to the new place while you stay in your current home, pick cheap furniture, use a credit card with good terms, look into loan options like personal loans or home equity credit lines, try out the market by listing the place with few furniture pieces, aim for easy-to-change furniture for flexibility, and talk to pros like real estate agents or home decorators.

Professional landlords do not operate out of fear and will ultimately operate a more efficient and profitable business.

Feel free to reach out for more insight on the lending process in the U.S. as it can help guide the property you ultimately invest in!

I've had issues with PayPal for that and ultimately lost the money and the product I sold on eBay.  

Ultimately, we will live in the STR as retirees, and occasionally use it for vacation. 

This is after rent appreciation, as well as selling 5 doors and taking some great profits from market appreciation and paying off other properties to lower our debt - which significantly boosted our cash flow.