So long as the Decedent named a Beneficiary for the 401(k) account , there would be no offset as you describe. However, if the Beneficiary is the Estate of the Decedent then the proceeds would be subject to the reach of creditors.
Under Federal law, a 401(k) participant must name his/her spouse as Beneficiary unless the Spouse agrees in writing to name someone else AND that writing is notarized.
In this case, if the Decedent was not married
at the date of death then he/she is free to name anyone as Beneficiary.
The asset would pass by operation of law directly to the Beneficiary and thus avoid probate.