You can disclaim the IRA . It must be in writing and delivered to the person or entity who is holding the property (in this case the IRA provider) within nine months after the death of the original transferor .
Here is a great Morningstar article to read through and ensure you meet the conditions.
I inherited my mothers Ira and I have 2 brothers
This money was to be split equally between us
However my 2 brothers agreed to fill out a disclaimer and give their portion to me.
My oldest brother turned in his disclaimer and it has been accepted.
My other brother has not turned in his disclaimer for several months now. Merril Lynch says they can’t distribute any portion until they receive his disclaimer. I don’t care if he keeps his portion, but I don’t understand why myself or my older brother can’t get our money until my other brother turns in his documents