Question
Without even telling us he was dating, our son who is away at college recently got engaged to a young woman he met on his own on the campus outside the auspices of a shadchan or anyone who could give him proper guidance. We were concerned about this and we really wanted to meet her. We invited her to spend a weekend with us and she came dressed in a miniskirt. We soon learned she wears miniskirts every day and that she will not cover her hair after she gets married. She apparently follows a brand of Orthodox Judaism that is permissive of many things our family and community and local rebbeim consider unacceptable. And it appears our son has viewed his relationship with her as a license to adopt that lifestyle which she exposed him to and engage in activities we taught him were forbidden. We are utterly embarrassed and devastated! They are evidently moving forward quickly with plans to wed because she wants her grandparents to be at her wedding and she does not know how much longer they have to live. They might even marry during the semester break less than a month away! We are unprepared emotionally for this. He only recently broke this news to us. We have not even met her parents in person. They live far away. We met them a few times on video. They are nice people, but their Jewish values seem to different from our. Our son has been over their house more than once and says they are nice warm people. They like him a lot and are happy to have him as a son-in-law. This young woman is not bad. She seems like a very nice girl who is warm and caring and very intelligent and wholesome. Our concerns are that he is rushing this relationship when they only met at the beginning of the semester, and she is detracting from his religious observance that he was always so scrupulous to follow in the past. All might seem well early on, but they are both very young and naive.

Question
Why must we use a cup to rinse our hand before saying a brucha. The question is on the cup and not simply using the faucet.