Oh:

"she could have received her share from other assets of the same value correct."

No. IRA is an Account. Not "assets." Whatever the holdings in the Account, it is just an Account. That's why putting certain investment types in an IRA makes no sense. Everything that comes out of the IRA that is taxable is Ordinary Income, even if it is gain from the sale of Stocks or State Bond Interest.

It is a convoluted subject, and it is not something to try to teach yourself. It is good you asked, but use the IRS and other resources, too. I really like the Investopedia articles.