Hmmm I’d like to chime in if you don’t mind, just a different perspective. Might be quite long tho, sorry.
I think something I’ve personally learned is that no matter what medication, it’s fine if someone sees and finds out about them.
Personally, I have to take 3 types of meds daily in quite significant doses to maintain foundational stability. There used to be a time where I had them hid and was self conscious about it, so if someone found them and asked I’d probably react not too well. But now, they’re all in one box (it’s always a 3 months fill, so it’s a lot and takes a bigger decorative box to fit inside) and if someone asks, I hide nothing. I just simply state my diagnosis and don’t get bothered at all. If someone wants, I encourage them to even ask questions bc they’ll understand better, learn something real and new about the condition, something that isn’t exaggerated by media and in turn stigmatized. It’s been a few years since I’ve been diagnosed and I’ve learned to live and accept that without issue. To me, it’s just like any other body ache/problem meds you could take.
The way we react to being asked about an ailment of ours usually directly affects the reaction we’ll get. Yes, it is a pretty serious condition but it doesn’t mean I’m, or anyone else in that regard, any different of a person than I was before they found out. It’s a part of me, only like a patch, I never chose to have so feeling bad about it or downgrading myself because of it is unfair not only to me but others as well.
A question asking why one takes specific meds and/or what they’re for can come for various reasons- usually they come from place of sincerity and care, even if we don’t see it as such or get irritated. If my meds were left somewhere a person could directly see them, I’d only agree that I was the one that left them there so responsibly for them finding out and asking lays on me. Sometimes it’s also better for us long term for the question to be asked bc if it’s the right person, you can gain someone who’ll support you. Depends on a person, but communication indeed is key no matter what, where, and with whom. Now, in the hindsight, I have to admit I regret/ am sad that in some cases I resolved to irritation and was unkind with my choice of words and approach. I wish I had handled it better back then but recognize that the reason it happened is exactly the lack of stability provided by well fit pharmacotherapy and exhaustion. If it weren’t for these, the situations wouldn’t have taken place.
Sorry for the long yap and thanks for coming to my tedtalk :)

If that was me, I would have just ignored that I even saw them and not go get them and read what they are for. Pretty disrespectful I must say. I'm big on privacy so I always wait for ppl to tell me stuff about themselves & not go snoop around lol. I'm just gonna ignore what the mc did tho it's not a big deal anyway bc it's manhwa and not irl and he didn't start a conversation on those pills thankfully.
It just reminded me bc I have had that same thing happen to myself and it was awful, the person even asked me themselves when they found my pills that why am I taking them even tho, they already read what they are for. It's like why do you think I want to have a conversation about my pills and everything that is involved with them with you when I wasn't even the one to tell you about them? I just ended up shouting at the person and kicked them out of my apartment. The audacity.