Should he be exposed to all liabilities that comes with it such as lawsuit, history of insurance claims(I believe insurance have a data base of past claims that can affect future coverage), credit and what not at an early age? 

I'm looking for the cleanest & most visible way to access payment history, see amortization schedule, tax documents, etc- much like bank softwares provide. 

A debt service loan would be a good option if your DTI is high, you want to close in an LLC, you're self-employed or have low income on paper, or you don't have a stable 2-year work history.

It helps readers a lot by providing context, and those of us who have some time in the market can look back into our histories and give you some advice. 

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

It is a very competitive market and units in the tens of thousands.

@Jay FayzIt's possible to use an FHA loan with a 5% down payment, but keep in mind that the loan is intended for primary residences, and you'll need to live in the property for at least a year.

Keep in mind we are talking ten's of billions in real estate.

Verifying last 2 years of rental history very important!

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?