This option has proven to be a true 'Best kept secret' in the purchase of real estate.
As others have stated, you will need to consult with the accountant, financial adviser and/or attorney.
What you REALLY need to focus on is purchasing the home via a 'self-directed' IRA. Even if the granddaughter fails to fullfill her obligation, there are significant, enduring benefits. This is not a complex process, but you will need a guide. If you want preliminary data before consulting the PROS, give me a call and I'll send you the link. If you are serious, you know what to do. If you are not serious you will use that 'contact' link.
Best of success,
Annette Lawrnce, BrokerAssociate
Remax Realtec Group
Palm Harbor, FL