I don't know about Washington state law, but Illinois recognizes a cause of action for harassment based on sexual orientation or preference. It is not clear to me whether your boyfriend is straight, bi- or something else, but it sounds like workplace harassment nonetheless. Your friend should review the employer's workplace harassment policy and report the matter to management. He should report the matter regardless of whether or not there is a workplace harassment policy. He should keep a journal of everything that happens and be watchful of any retaliation from management.
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