Read this article at TreasuryDirect.gov: https://treasurydirect.gov/savings-bonds/cashing-a-bond/
It is perfectly understandable that you would not have known about the bonds, and there is no time limit for cashing them in. But remember, you will owe all the taxes for the year in which you cash them. That could put you in a higher tax bracket. And if you are on Medicare, it could result in an increased monthly premium!
First use the link above to get the current value. It will be more than double, since EE bonds had variable interest payments. You might choose to cash half in this year, and half next year. YOu’ll need a death certificate, and will have to send the paper bonds in to the Treasury, unsigned, along with form 1522. Instructions are in the article above.