Legal Question in Landlord & Tenant Law in Washington

There is nothing that obligates the landlord to deal with you, since they have no contract with your name on it, and since you are not a lawyer, licensed to represent people, no, they are not obligated to recognize you as your boyfriend's agent in this negotiation.

Let me also be highly critical for a moment. If you want to "legally represent him," that requires a license to practice law, otherwise, you are practicing law without a license. This is a crime in Washington. Mind you, it is one people violate all the time, but most do it unknowingly. Now you know.

One last point. The rental agency may not agree to speak to you due to liability reasons. If your boyfriend later claims he does not know you, has never heard of you, etc., and they negotiate something with you, that can quickly come back to haunt them. Hence to avoid any possible liability, they may only agree to speak with your boyfriend.