Should I Apologize?

I wrote a post a couple of days ago about how I attended my best mate's barbecue and while everything went well at first, I found it difficult to make conversation and I felt left out. I stayed as long as I could tolerate, but eventually and abruptly said goodbye to everyone and left. My best mate didn't like that I left, but I apologized to him and explained the situation. Now I've been told that his autistic older brother is fuming because of how I chose to leave. I didn't go out of my way to offend him nor anybody else at this barbecue, but apparently now he wants me to apologize to him in person. I don't know whether I should do so again or whether I should go round the house again until this blows over. I don't want to be Mr Sorry just because I made a rash decision based on my insecurities due most-likely to my own medical condition.
What do you think I should do, bite the bullet and say sorry just to make peace, or just not bother and let these ill feelings he has pass?

I wrote a post a couple of days ago about how I attended my best mate's barbecue and while everything went well at first, I found it difficult to make conversation and I felt left out. I stayed as long as I could tolerate, but eventually and abruptly said goodbye to everyone and left. My best mate didn't like that I left, but I apologized to him and explained the situation. Now I've been told that his autistic older brother is fuming because of how I chose to leave. I didn't go out of my way to offend him nor anybody else at this barbecue, but apparently now he wants me to apologize to him in person. I don't know whether I should do so again or whether I should go round the house again until this blows over. I don't want to be Mr Sorry just because I made a rash decision based on my insecurities due most-likely to my own medical condition.
What do you think I should do, bite the bullet and say sorry just to make peace, or just not bother and let these ill feelings he has pass?

You’ve already explained and apologised why do you need to do it again.

Apparently it'd be more meaningful if I apologized in person.

Who said that him or his brother? I don’t get that though like you literally already apologised but it’s honestly up to you.