To protect yourself, make sure you have a great property for STR. 

Anything I need to be aware of or make sure they do for my protection?

My humble advice to anyone attempting to do creative finance is:Creative finance is for experienced investors who have access to capital if anything goes wrong.Learn the lawsDon't use a contract "off the internet", laws vary by state and are also regulated on a federal levelLearn the financing techniques correctlyDon’t skip parts of the processDon’t ever do a “kitchen table” closingUse the proper deedAn attorney can help you with the legal work, but the rest you are on your ownYour guru will not bail you out“Investing” in someone else’s deal by providing a small 2nd loan so the “investor” can pay for “cash to the seller” and for “closing costs” so he can do the deal is a very bad planKnow what problems can ariseLearn the responses and solutions to problems before they are neededKnow everything there is to know about Title and what that meansKnow who a "protected class" individual isLearn the "back doors"Learn human natureUnderstand timelinesUnderstand regulation enforcement (some of these "mistakes" have a 10 year statue of limitations ( they can charge you 10 years AFTER you do the transaction) and carry hefty fines and possible imprisonmentThe court doesn't accept "I didn't know" for an answer"Know that the source of the lead plays a serious role in some states and federallyKnow how much of a "profit" pushes the boundaries to invite an investigationYou can be sued by the seller if you don’t do things correctlyYou are automatically at fault if an investigator or attorney or regulator gets involved.

Whie DOS lender risk may or may not be high, being ininsured is... well, enjoy your 'asset protection'.

Credit cards offer a lot of protections for the user, but that doesn't mean they are allowed to commit fraud with them.

If you choose to play with fire, that is your perogative.For your reference, here is a good primer.Here is the key paragraph:Rental discrimination is when a landlord or property manager treats an applicant differently based on the applicant’s inclusion in a protected class.

Since they (banks) have FDIC protection and these other "trust" custodian do not I am now looking at how to protect what we have.

How do I protect myself in this situation, while also helping a relative? 

We have a 14-page management contract that we've added our real experiences to over the years, with the intent of protecting both us AND the landlord.

Make sure any lease agreement you use complies with Arizona's landlord-tenant laws, including required disclosures (like bed bug information, for example).If you're unsure, consulting with a local real estate attorney to review the agreement can provide peace of mind and ensure you're fully protected.