If the saving bonds are in her name, then she is the only person entitled to them. The grandchildren have no claim on them. Saving Bonds are a 3 year term product. Have a look at the purchase date as maturity date is exactly 3 years later. They can of course be withdrawn anytime by the holder but interest will be less. If they are more than 3 years old withdraw immediately as no interest is added after the maturity date. The holder is written to and given two options (a) withdraw in full or (b) purchase a new saving bond with the money.