回複：請幫忙.老婆的RFE, G-28

no, you are not qualified to be the legal representative (one of the three types). You should write a letter explaining why she does not need G-28. I also assume she (or you) filled out all her I-485 related forms and signed only by her. Because you cannot have other people prepared and sign the documents and not also enclosing G-28.