There are a lot of missing details in this:
1. What is the source of the money? Is she a "silent partner" in some sort of business that her father has, or something else along those lines? Or is there a trust setup by her father that the money is actually coming from, and not directly from her father? The fact that she thinks it would add to her taxes indicates it is something other than a traditional gift.
2. Is she self employed? She could deposit up to $53000 of income into a SEP IRA if she is. If she's not self employed, then depending on her other income, she could deposit a portion of the money into a traditional IRA (up to $7000 depending on age) or simple IRA (up to $16000) if her employer has one to possibly save on taxes. And if she files jointly with her husband, she could also deposit some into an IRA for him to save even more. What is her income level without this money? Did she state she deposits all of it into an IRA, or was she maybe referring to just depositing some of it? Was she referring to saving on taxes in the year she receives the money, or was she possibly referring to depositing it into an IRA to save on future taxes?
If I had to hazard a guess, I would say this is has to do with a family business or a trust, and she is utilizing something like a SEP IRA. But that's based on a whole lot of guessing.