Gifting each parcel to the other has no benefit that I can think of.  

One side issue, what if mom needs a nursing home.....I've read elsewhere that the Medicare folks are smart enough to ask: "does mom own a home or other assets that she should use to pay for her nursing home (and exhaust those funds) before Medicare pays more.....and they're smart enough  to ask "has she gifted her home to the kids in the last 5 years?

@David Bellmont Yes, this is all possible.You'll need to obtain financing to purchase all the properties... and you'll need skin in the game or a gift of equity. 

She cannot just, gift, sell or transfer 20 properties she owns personally to her IRA.

Here in Texas the most you can give to a non-licensed person is a $50 gift card. 

I'm not a CPA, but if this was given to you when your aunt was alive then it was a gift, not inheritance. 

He can gift you the funds for purchase.

So, do I need to tell the bank the money was a loan from my mom versus a gift to qualify for delayed financing?

Acceptable sources of down payment funds - HELOC on other property- Cash out mortgage on other property - 401k loan Unacceptable sources of loaned down payment funds- Loans from friends or family- Gifts from friends or family- Cash advances from credit cards- Secure loans in someone else's name (for example a HELOC withdrawn from your parents home)

That’s the place that gifted you all that equity in such a short time period.