TIFU by calling out my cousin's behavior, but at a really wrong time

Hi all, this is basically a post from a new account as my family knows I use reddit. Also English is not my first language. This is a long read. TLDR at the bottom (TLDR generated by ChatGPT)

So I (30 M) have always had a tense relationship with my cousin Greg (39 M). He is a cousin from my father's side. While our families get along and we visit each others homes during holidays or festivals and regularly update each other, my interaction with him has always been tense since childhood and we rarely talk/call/message each other to the point where Greg talks more with my younger brother Charlie (27 M) to ask how I'm doing or anything related to me.

Reason - Greg has basically bullied me through from my entire childhood to even now. He still talks to me like I'm still a child and often puts me down passive-aggressively and often making fun of my shortcomings and always trying to show he is better than me, for almost anything, be it -

• my physical aspects - I am shorter and on the chubbier side, while he is tall and athletic and regularly plays sports and works out since his teenage years.
• my way of talking - he calls my way of talking or using certain terminologies as outdated and often says that I explain things too much in detail and just tells me shut up when he feels that I'm bothering too much.
• my lack of dating experience and reluctance to get married - I haven't had much success in dating and am still a virgin and am also reluctant to get married due to personal reasons. While Greg became a fuckboy by the time he turned 15 and always used to brag about his dating experience, saying how many girls he dated or banged, till his mid 20s. He got married in late 20s to his best friend Amy. She knew about his past and had dated a few guys as well, so one could say they were compatible in that regard. They have a daughter, Emily who recently turned two, Greg and family live abroad for work.
• even my profession - Greg calls my way of working as useless, even though we are in the same profession, but in different roles.

The only time Greg and I have even talked in a normal manner was when we talk about video games (coincidentally a shared hobby of ours) and when I asked him for help regarding my job around a few months back. He did give me useful tips on how to ace interviews, build my resume and even helping with his contacts etc. All good advice if one ignored his condescending talks and again trying to show that he is superior to me.

However there were some things I noticed or got to know from my family which basically made me realize that Greg is not the perfect person he claims he is -

• Greg was physically and mentally abused by his mom and dad when he was a kid in order for him to become more "tough and masculine". Greg's older brother, George (now 46) didn't give a shit about Greg being abused, because he had also gotten used to it as a kid and told Greg to suck it up and "be a man". That was the reason for Greg to focus on working out and playing sports since this kept him out of home most of the time and also bullying me to feel good about himself since he couldn't confront his brother and parents.
• Greg and George are understandably not that close, but Greg's college education was partly financed by George and Greg was also dependent on George financially when he shifted abroad for work.
• While pushing me to setup a dating profile a few years back (and making fun of me) - Greg inadvertently revealed that things are not great between him and Amy by saying multiple times that there is a huge difference when a girl best friend becomes your girlfriend or wife as her behavior completely changes and you see a side of her which was either kept hidden or ignored when you were only seeing her as a friend and to be careful if I tried this with my female friends.
• Amy married Greg mainly for his money.
• Additionally, Amy's father had taken money from George a few years ago and was struggling to pay it back. (I'm not sure if Greg knows these issues).

Now that the prologue's out of the way lol, So here's where I fucked up

Greg's mom (70 F) recently died of a sudden heart attack after being admitted to a hospital for a routine check up last week. It was quite a shock for all of us. George was handling the funeral while our family helped in whatever way we could, providing help with logistics, paperwork, and emotional support. As mentioned above, Greg and his family live in a different country and they couldn't arrive due to visa issues, but were present through video calls.

I had also recently left my job due to personal reasons and moved back home. The only people who know are my family and some close friends.

Recently Charlie spoke to Greg and accidentally slipped out I resigned from my job. Greg immediately flipped out and asked to hand the phone to me. He asked me if what Charlie said was true and I confirmed the same. He then became apeshit and started calling me names, saying that even at 30 I still haven't got my shit together and how long will be dependent on my parents and when will I even grow up and get married or even stick to a job, called me a fat virgin loser etc.

Listening to him and especially the way he talked just triggered something in me and all those memories of being bullied by him came back. Charlie could see that I was just ready to explode and tried to calm me down, but I just couldn't control myself any more and just blurted out and said things along the lines of "Sincerely fuck you, Greg. I'm sure your mom and dad are proud of you behaving this way, seeing the kind of man they raised you to be. You were not even here when your mom's dead and me and my family are handling everything with George. And thanks for the dating advice, but its best to take care of your own house first. Sure I am a fat virgin loser and you are some Olympic athlete, but we all know why Amy married you. Fuck boy and a gold digger is a match made in heaven. I am sure Emily will love to hear how many women you banged when she grows up. I would love to see your reaction when she finds someone like you when she starts dating".

Needless to say it wasn't a great conversation. And I could see that Greg was kind of shaken, he just said "fuck you" and cut up the call. During this call, Charlie was present and my parents came in my room and saw the whole thing. My parents and Charlie weren't happy by my behavior at all and my dad said to me while it was understandable that I was angry at Greg, that this wasn't the right time to go off on a rant considering he just lost his mom and was acting out. Things have kind of been on a thin ice with our families as of now. Greg and his family will be arriving next week and my family told me it would be on me to fix things with Greg, but they would support me if I chose not to.

TLDR -
I (30M) exploded at my cousin (39M) after years of bullying, mocking, and condescension—especially after he berated me for quitting my job. I said some harsh truths during a time of family grief (his mother had just died), and now things are tense between our families. I'm left deciding whether to reconcile or not.