Personally, I've felt the investment has been poorly run in almost every possible way.

They paid their portion of the rent.I have found a lot of investors bring their personal or political feelings into the investing conversation. 

So, things change a bit.If it is his personal home, there are more restrictions.For an investment property, if you take over his financing, read through the deed of trust (mortgage) and see how they handle transfer of ownership.

For instance, said property manager manages maintenance issues, problems that arise during bookings, basically anything that needs a physical person at the property, while I manage the rest?

Point noted about not being able to underwrite without seeing things in person.

Lots of loan options can close in an LLC, helocs usually need to close in your personal name.

The property is insured on your behalf, personally. 

Quote from @John Friendas: As a person with an average salary, I was wondering what the maximum amount of DSCR loans a lender would give out would look like?

I am here to create a business strategy that protects personal and business investments and mitigates risk,  procure a coach or mentor, and set up tax strategies to create long-term wealth for myself and my family. 

If you make the person an LLC employee you can get around it, but partner does need to be careful.