I think it depends.

My dad, my brother and I are on group text (sometimes adding other people as needed) and we communicate in this 3-way all the time, several times a day since our mom died.

I am in other groups texts and group emails with groups of relatives or other groups of people. I think if it’s how family communicates, then it’s fine. Of course we call each other but we communicate a lot and if I call individual people every day I’d be on the phone all day

I don’t think Facebook is better as not everyone is on Facebook and it’s more impersonal. If people aren’t on Facebook they won’t even know what happened

Just in my opinion.

As about death in the family it’s hard to tell. When my uncle unexpectedly died this winter, I found out from my cousin who called me crying. I called my dad because I did want to talk and knew he’d be just as upset (uncle is my aunts (moms sister) husband). But then I texted bunch of people. I was too upset to keep calling plus calling is time consuming.

I think in your situation if your brother and you aren’t close, he maybe felt more comfortable group texting versus calling

I personally like groups texts and group emails because it saves us time and we can share opinions and feelings and engage in a conversation between all involved and all talk to each other, versus talking to one person at a time. It’s not impersonal the way it’s done in my experience. People of all different ages use it very often in my experience

But I understand not liking it. I personally don’t like social media. And everyone else loves it. I think is subjective. It’s ok for you not to like group texting

I had to add that if group text included strangers, I’d be taken aback.
But if it was just siblings or other close family, then I’d had no issue with that. If someone wanted to inform me and my brother together (and maybe spouses and adult kids included) instead of informing us separately, I’d have no issue with it. It’s a family so family can learn about it together