My question involves landlord-tenant law in the State of: Washington state
My son was part of the 3rd set of tenants on one lease. The original tenants left and my son's roommate and his girlfriend took it over. The girlfriend had a "comfort" animal (cat) that peed all over the carpet, leaving stains. When she left, my son moved in. He had to sign a new rental lease for the remaining period on the lease and a checklist that had been done three years prior, showing that there were already issues with the carpet, the landlord having marked it as "NOT OKAY" on the checklist. The landlord had him sign a new Apartment Lease Agreement along with a Roommate Change Form, where it states that the landlord would "not be doing any refurbishing of the unit prior to my occupancy. I understand that I take over sole responsibility for all cleaning charges and damages due at the end of my tenancy." Now, they are charging him for the carpet and padding as well as Kilz -- damages done by the former tenant's cat. The complex is a NO PETS complex and my son is allergic to cats, so he does not now, nor has he ever, owned a cat. And because the cat was a "comfort" animal and needed special permission to be in the apartment, she had to register the cat with the landlord, so they know that SHE is the one with the.
Is that clause regarding him being responsible for all cleaning and damages that he DIDN"T cause legal? Isn't there an RCW in Washington state code specifying that they cannot charge him for damages HE or HIS guests caused? Shouldn't they be going after HER?
Thank you for your help.

