This seems like a bad idea to me as well, as it would be a dual relationship. And are you doing this for her for free? Couldn't she get someone who is not a client to help her? The fact that you'll be sitting with her in her house (I assume you don't meet with her there) seems like it could affect the therapeutic relationship and make the boundaries more blurry. If you say no, she shouldn't (in theory) hold it against you. If she thought a long time about asking you, that suggests she also has doubts about whether it's a good idea.