They can sign the tenant to a new lease that starts after your ownership. 

A quit claim deed costs nothing more than the cost to record it and will transfer ownership.If you sell and your cost basis is zero, you might be liable for tax on the entire price.If they transfer ownership to a trust which you are the beneficiary of, when they pass away, you inherit at the current market price and only pay capital gains on the gain from that date.I recommend consulting your accountant to see how this applies to your current situation.

Looking to buy out of state, what is the process?

If you do the actual math on the true costs of home ownership, it usually* doesn't pan out as a better investment than renting.

And a site dedicated to real estate investing and not small business ownership isn't the best place to ask them. 

I think you need to start being firm with the tenant and tell him what the expectations are for your new ownership.

Although you have not supplied all the detail (a type of ownership and such), there is another complicated way to report this as partnership return, and their portion of the expenses as non-deductible expenses on your partner's side.

I'm oversimplifying it a bit but an upset sale does not really divest anything but the ownership interest in the property.

Good Afternoon All, I am writing this post as I am looking for some guidance on how to approach a shared ownership of a rental property.

I assume he's going to have a share of ownership, so his money will be protected via his legal title to the property.Be careful...spell everything out on paper.