This will depend on how the property is actually titled. If it was jointly held property your Mother will automatically by operation of law own the property. However, if it was owned in another manner this may not be true. You should go to a local probate attorney to determine if a probate of the estate is necessary after a review of the entire estate.
Any individual seeking legal advice for their own situation should retain their own legal counsel as this response provides information that is general in nature and not specific to any person's unique situation. Circular 230 Disclaimer - Advice given in this response cannot be used to eliminate penalties with the IRS or any other governmental agency.
Just stating "and" does not necessarily make the property joint tenancy. You should have an attorney review the documents, especially since married persons in WA tend to hold property as Community Property.
Also, you need to find out if your parents ever signed a document known as a Community Propertry Agreement. This is a formal, notarized document. It gets recorded after the death of a party and automatically vests the title in the survivor.
Otherwise, a formal probate would probably be necessary.
This posting is not intended to be relied upon as legal advice for a specific situation.
Whether the estate needs to be probated depends on how each item is titled. All property held as joint tenants with rights of survivorship will be able to be transferred to your mother once she has provided the institution with a death certificate. However, property held in other ways (tenants in common, for example, or just jointly without the right of survivorship) may need to be probated to be transferred correctly to your mother.
I would recommend meeting with a local probate attorney who could look at all pertinent titling documents and assist your mother with the decision of whether to file a probate.
Disclaimer: The information contained in this answer is designed to enable you to learn more about the services that Brown Yando & Kampbell, PLLC offers to its clients. This information does not, and is not intended to, constitute legal advice, nor is it intended as a source of advertising or solicitation. Your use of this information does not create or constitute an attorney-client relationship. You should not consider this answer to be an invitation for an attorney-client relationship. You should seek the assistance of an attorney to provide you legal advice based on the specific facts and circumstances of your particular situation.