She can only validly marry a Jew if she had already converted of her own free will without any relation with that marriage. If it was so, she is wellcome, but her family must not convert just to follow her. If she validly converted and her parents want to follow her in abiding by the Torah, then they must live as Noahides, not as Jews. But if they come to know Judaism through her, and really wish to be Jewish to worship Hashe-m in the Jewish way ( and not just to follow their daughter) it's ok for them to start the process. Anyway, I think the Clintons have to change a lot to become either faithfull Noahides or Jews. Weren't they supporting abortion in the past? if they couldn't respect 7 laws, I doubt they can take 613 upon them.