Sorry this post is long, there's a lot of context. I (22NB) live at home with my parents and two younger siblings (17F and 14M) for both financial and personal reasons. I have several disabilities, including autism, which I was diagnosed with when I was very young. I love my parents, but they’re overbearing, and despite how much ‘support’ they show they don’t seem to actually listen to me. My mom especially treats me like a child, and always tries inserting herself into my social life when it isn’t needed. I don’t think either of them fully understand that I don’t have the mental maturity of a toddler anymore, I just have somewhat different needs/abilities than the average adult. So when I started having regular hookups a few months ago I didn’t share much with them beyond when and where I was going to have social plans with friends (not technically a lie), and they're pretty much always okay with me hosting friends at our house (though that's probably because they're just happy I actually have irl friends to hang out with, lol).

Last weekend my family was out of town while I watched our dog, and I decided to have one of my FWBs (22M), who I’d already hung out with a few times and trusted well enough, stay over for a night. I’m a very paranoid person, so even though I trusted him enough to have him over I still took several precautions beforehand—making sure valuables were hidden, locking my siblings’/parents’ rooms, keeping the dog nearby so I could still care for him, etc. The one precaution i didn’t take was actually telling my family he was coming over (I did tell a few friends in case anything did happen). But despite my anxiety, the sleepover went very well—that is, until my FWB had a seizure the morning after. He hadn’t told me he’d had seizures before, and I’d never handled a person having one before, so I called 911 and had him taken to the hospital. Once he was there everything quickly worked out, we texted back and forth, he apologized for not telling me he has epilepsy and we figured out a gameplan in the case something like this happens again. It was a crazy situation, but in my mind it had been resolved long before my family got back home.

Tonight my sisters (24F and 17F) and I were hanging out and I told them this story, trying to be lighthearted about it because both me and my FWB thought it was pretty funny in hindsight, and my sisters and I usually gossip to one another about dating and similar topics. My older sister also thought it was funny, but my younger sister got angry, scolding me about how dangerous it was to invite a stranger over to the house, because I could have been seriously hurt, and even besides that, “This isn’t just your house, everyone else’s stuff is in it too”. She asked me a lot of questions about my FWB and what happened, and I tried telling her about all the precautions I took, but she was still upset with me for not saying anything to our parents beforehand, or even telling them about the paramedics coming over. I tried explaining that because the emergency had resolved itself that I didn’t find a need to bring it up to our parents, especially because I know if I brought it up they would freak out and make a huge deal about something that was already over and done with. My older sister backed me up on that, reminding her that they tend to baby me a lot more than they really should and that it makes sense that I wouldn’t share a lot of info about my social life with them. Still, younger sister continued lecturing me about how dangerous and gross it was for me to hook up with someone while the family was out of town and not telling anyone about it. I continued trying to defend my actions, but older sister eventually had to discreetly text me telling me to drop it, so I did and simply apologized to her.

Now that I’ve thought about it, I do think it was probably a bad idea not to say something to our parents, especially because unlike previous hookups, I didn’t even tell them that I had a friend over this time, so they're completely in the dark about this. I may be an adult, but I don’t own the house, so I do feel bad about not telling them, especially because of the possibility that something worse could have happened. The only reason I still haven’t brought it up is because I try to tell them as little information as possible about my social life as a sort of boundary so they don’t try to overstep like they always do, and I honestly just don’t want to start a fight about something that’s already over and done with. But I still feel guilty about this whole thing, so I might as well ask a neutral-ish audience if what I did was shitty or not, that way I can at least know for the future.

ETA: well, these comments have definitely confirmed my suspicion that i was right to feel guilty. I was very lucky that things went as well as they did this time, but I really should have just asked my parents beforehand, and in hindsight it was really stupid that I hadn't done so to begin with, since I usually do take the precaution of asking first and my parents don't usually say no to me inviting someone over. Lesson learned, thanks for your help :)