How to urchase using subject to

[Brandon Kessler]

Looking to purchase a condo from a freind. He moved to Dallas and he has been paying his HOA and morgage for several years now all wile the condo is vacant.

I approached him about purchasing it and he seems very interested.

I am looking to purchase it by means of subject to. He still owes about 70k on the property and purchased it around 110-120. Several years back. From what I'm looking at it may be worth around 140k-150k currently. 

Without pulling a laon and making this a win win for us both, how can I structure this and approach him with this plan. He seems very motivated. I dont completely know how to arrange this to happen on top of making him aware that this is common and not illegal. Knowing him he will question it. Lol

The reason I'm doing subject to is because I'm currently fixing my credit and probably will not qualify for a loan.  Thank you for any help guys.