I receive many calls from clients with similar situations. You say you "know he left a law will." How do you know this? If you know who your grandfather's attorney was, you may be able to get some information that way. The county probate court would have a record of the Will if it was filed with the court for safekeeping prior to your grandfather's death, but this happens in only a very small number of cases. If the Will was ever probated, then you would presumably have been listed as beneficiaries or interested parties, and you would have been sent a copy, unless the Personal Representative claimed they did not have an address. You should be able to determine this by checking with the probate court.
The fact that your grandfather was married at the time of his death suggests something else. A Will only covers property titled in the decedent's name alone. Anything held jointly would automatically pass to the surviving joint tenant(s). The same is true with property subject to beneficiary designations. My guess is that all of your grandfather's assets were titled in joint names with his wife, or he designated her as beneficiary. You may be able to check online property records to help confirm this. That would explain why you never received notice.
I agree with Mr. Frederick's very thorough response. I receive similar calls and oftentimes a person having a Will is irrelevant because all property passes to the joint owner and named beneficiaries. The only time a Will is filed with a Court is when the deceased person has assets in his/her individual with no joint owner or beneficiary. Most states, not sure about WA, require that a person in possession of a Will of a deceased person file with the Court (don't confuse file with the Court and filing and seeking admission of the Will to probate). Filing a Will with the court is a simple method to preserve the Will for later possible use if property is discovered in the deceased name.
Best of luck.
Mr. Post is licensed to practice law in KS and MO. The response herein is not legal advice and does not create an attorney/ client relationship. The response is in the form of legal education and is intended to provide general information about the matter within the question. Oftentimes the question does not include significant and important facts and timelines that if known could significantly change the reply unsuitable. Mr. Post strongly advises the questioner to confer with an attorney in their state in order to ensure proper advice is received.