AITA For Not Telling My Brother That I Lost My Spleen?

AITA for not telling my brother that I lost my spleen?

Okay, so I don't think I'm wrong here, but he's been really upset (not mad, but he gives me these really sad looks that make me want to apologize over and over again).

Background:

I (m17) lost my father a year ago. My brother (N, m24) focused on my new little brother (R, m11, we just found out about him, mom not in the picture) because he thought I would handle myself. R and I didn't get along initially because we were jealous of each other and he took every opportunity to antagonize me. N took away something very important to me and gave it to R without telling me, and I found out when I walked in on R gloating. N's defense was that he knew I wouldn't take it well so he planned to tell me later, and that R needed it more. We argued and both said some things we wish we could take back.

(I don't blame him for any of this anymore, it was a very hard time for all of us and he was thrust into our father's shoes while grieving. We've talked, and I know he did what he thought was best for me and R, because he believed placing me as an equal to him would show that he trusted me. But he apologized for not understanding how much taking it away would hurt me and that I still wanted to be a kid, not an adult, and I apologized for not being more understanding of his position. We've moved on and are working on our relationship.)

Anyway, the main conflict was that I believed our father was still alive and nobody else did. My other older brother (RH, m21) was the exception, but he's estranged and didn't want to get involved.

(Side note: my siblings except for R are all adopted by our father, but I got emancipated after his supposed death)

N said I was going crazy due to grief and insinuated that I should be locked up in Arkham (an asylum in my city for the criminally insane). I chose to leave to find proof that my father was alive.

Fast forward six months and I found proof, but in the midst of it, I had to have an emergency splenectomy. When I came back and gave them proof to bring my father back, relationships were still strained so I didn't tell anyone. We reconciled in time, but I still didn't see the need to tell them as it wasn't important to them.

The issue:

A week ago, R caught a nasty flu. N wanted me to give him his medicine, I declined. N, frustrated because he thought I was just being difficult, told me to just be nice to R when he’s sick and that it won't cost me anything. I snapped back that it may cost me my life, not that he would care.

Something in N's expression shattered, and he let out a little, "what?" I remembered too late that I didn't tell him I lost my spleen. I tried to backtrack, but he kept pushing until I finally admitted I lost my spleen and under what circumstances. He was devastated, and I felt really bad for not telling him because he looked like he was on the verge of tears (he's really emotional, and that year took a toll on us and is still a sensitive topic). N asked whether it's because I didn't trust him, and I said I didn't know.

Ever since then, N has been hovering over me and bugging me about my health and diet and sleeping and working habits. He told the rest of the family and they've been overbearing as well.

N, however, still feels very guilty about the whole situation. I feel bad for making him upset, but I still stand by the fact that I did nothing wrong by not telling him. I think it was just unfortunate circumstances and that neither of us are to blame. R vehemently says that I'm the AH for never saying anything because my family and I engage in an activity that gets us injured frequently. He said I endangered myself and others by not telling them (he's worried about me and that's how he shows it, and probably also feels responsible about how I lost my spleen because his maternal grandfather was involved and he's got trauma surrounding him)

So, AITA?