<human>: Give me a shortened version of the text

So I used to be really good friends with this guy but after he went to college we drifted apart but then I started to get really close to his younger sister (She is 19 and her brother and I are 21). It's to the point where I am closer with her than I was with him and now she feels comfortable enough with me to tell me deep personal secrets. I am actually very happy that we got as close as we are and I confide in her as well (mainly about my failed and awkward attempts at navigating the gay dating pool) but I'm confused as to if I should be feeling guilty about keeping her secrets from her brother. Most are about stuff that shouldn't be his concern (her love life, social life, sex life, etc) and I have no business to tell him but as her big brother I know he would like to know some stuff. We also have gotten to the point where she told me she is getting a fake ID and wants to go bar hopping with me (tried talking her out of it but she is doing it regardless) and smoke pot with me. She knows I do both (I used to smoke with her brother all the time when we were closer) and I know that so does she (and a lot longer than I have too) but I don't know if I should because I was friends with her older brother first. He knows we have gotten close and fully supports our friendship but he doesnt know how close we have gotten. So basically I'm just torn about how I should be feeling. Advice?
<bot>: Was close friends with this guy but now am closer friends with his younger sister and I don't know if I am breaking some friend code or some shit like that. Advice?