sorry for your loss....
money contributed to a 401(k) or IRA is normally all pre-tax money, meaning there was no tax paid on it when it was originally earned, nor has any tax been paid on the earning that accumulated over the years.
When the money eventually comes out of the 401(k) or IRA, even if it is the beneficiary who withdraws it, the IRS is still seeking its tax on the money. The obligation to pay the tax does not go away just because it passed to the benefiicary, in this case from your husband to you.
