i think my sibling may be transfem?

I (14nb) think my sibling (12, will use he/him for now because I have no confirmation of anything) may be trans or at least questioning his gender, and I want to know if there's any particular way of responding I should have? I don't have any concrete information, but I do know that he: \- has asked me multiple questions about how being trans works (i'm not out to him as nonbinary, he just considers me his primary source of information) \- says things like "yeah, so i should go first" in response to phrases like "ladies first," and sometimes puts on a feminine voice and does this whole over-the-top impersonation of a girl, and I can never tell if it's a joke or not \- I noticed him looking at a reel one of his female friends sent him, which said something along the lines of "me and my homegirl" \- refused to cut his hair for the past couple of months, and came home today after getting a haircut, visibly upset about it (although he's been saying it's because the hairdresser 'didn't do what \[he\] wanted,' and hasn't specified what it is he did want) Anyways, I don't know if I'm reading into this or not. I know I'm nonbinary, but I am AFAB so I can't accurately imagine what the transfem experience is like, and I'm not really sure if I should even do anything in this situation. Some additional context - my parents aren't overtly transphobic but they are kind of weird about trans and queer people. I *am* out to them as bisexual, but it took a while for them to fully accept it, and I'm aware that it's selfish, but I always thought that if I couldn't necessarily make my parents proud as my true self, then my sibling, who, until now, I've always thought had more similar views to them, could. For this reason, I am kind of on the fence about talking to him about this, in case it opens a Pandora's box and he feels the need to tell our parents. But I'm aware that this isn't about me, it's about him and his relationship with gender. So, my questions are: am I reading into this, or does it seem like something is going on? And if it's the latter, should I talk to him about it, or should I wait until he tells me something? Again, if it's the second option, should I tell him about my own gender identity, or is that not necessary (he's very bad at keeping secrets, and previously outed me as bi to several people, so I want to avoid this if it's possible)? Any help would be extremely appreciated. Thank you :)