How much money? If more than $7000 (or more than $8000 if you are over age 50) that will affect the answer.
We need to know if your father's IRA was cashed out, or if this was a rollover of some kind (which might have been improper). And if it was cashed out, who will pay the tax, you or the estate?
If it was some kind of rollover, it may have been done improperly, or I might be misunderstanding what happened.
