Did she have a CCL? If not, then why did he leave a loaded gun with her in the car?
Not sure. I though Washington allowed loaded weapons in cars without a CCL? I would have to look it up to see. Either way, as an adult, she was the last one responsible, CCL or not. May not be completely legal, but the responsible adult thing to do would not be to leave a 3 year and an 8 month old in the car unattended, weapon or not.
WA allows legal open carry. So he or she could have just strapped up and walked on in the store.