Answer:
In most states, she would be the sole renter after the death of the co-tenant. That would put the box beyond the reach of the son or the estate. If the son is only the nominal executor and wants to search for a will, he'll have to ask his mother (or his father's ex-wife, depending on the circumstances here) to access the box to look for it for him.
Check your state law and provisions of the safe deposit lease for further information. If still unsure of how to proceed, the bank should seek legal advice before acting.
First published on BankersOnline.com 4/23/12