I think the answer is almost certainly "no." What you are proposing is called "practicing law without a license." He is allowed to represent himself, and you can certainly help him and advise him as his wife, but you almost certainly cannot appear in court on his behalf.
That's not legal advice as I don't hold Washington licensure. It's simply information based on general principles of law which is intended to educate. If you need legal advice, please consult a lawyer who holds Washington licensure.
Persons without licenses to practice law often are allowed to represent others in administrative hearings. However, to appear before a court and represent others, a person would have to be a licensed attorney.
Unless your husband's case is before an administrative judge, you would not be allow to represent him in court since you are not an attorney.
