Question about odd requirements from Freddie Mac

[Deon C.]

My son found a foreclosed home offered by Freddie Mac. He put in an offer and it was accepted. He plans to live in the home as his primary residence for 2+ years. He did this once before and now he is ready to sell that home for a hefty profit, but he can't sell until he finds another place to live. He told the agent I, his father, was going to loan him the money for the purchase until his other property sold. All seemed okay, then they demanded I sign a gift affidavit for the funds. We again said this was not a gift, it was a loan. They said just sign it as it just bureaucratic junk and to sign it or they would take the next offer that was just a little less than my son's. So I signed it and then when the final contract was received it said that "Purchase shall not uses any third party financing" and "Funds from any third parties will not be accepted by the closing agent." I planed to fund the loan out of my pocket and put a mortgage on the property to secure the debt. We have seen the e-mails from Freddie Mac and they seem to be absolute jerks even to the buying and selling agents. 

How deep down the rabbit hole are we on this one?