Help father retire/purchase properties

Hello, thanks for all the pod cast! I listen to it several times a week while I am walking my dogs. My situation is: I live in CA with my father in WI. I am 36 and my father 75 and single. My father owns 5 properties in central WI with one with a payment. I have been talking to my dad how I can and best purchase the properties from him. I did roll over my funds into directed IRA think that I could open an LLC to buy the properties from him. Then I heard in a later cast that I am not able to purchase the properties from my dad using the IRA LLC. I am married so maybe have my wife make an IRA LLC? What I am most worried about is that time will get ahead of us and the state will end up owning the properties. I would like to buy the land from my dad to help him enjoy a retirement. Could I have him but the properties in an estate and then I just pay him cash out side the system? I think this would prevent the tax man coming in since it would be considered a step up in bases. Let me know your thoughts thanks! Additionally, 3 of these properties my dad actively uses as a rental. The other is a 3 stall shop garage and the last is his residents. Is it possible that I buy the properties personally then add them to the IRA LLC afterwards? My goal would be to keep them as a rentals.