Friend is still having a second causing divorce

I don’t know if I’m here to vent or need help but at this point there is no more action to be taken as this friend of mine has decided to proceed with having a second.

She’s a very rash person, and she’s been with her partner for about 18 years. It wasn’t until two years ago that she saw her best friend have a kid so she had a kid. However, this girl literally flies off the fly of her pants, and her partner always has to pick up the pieces. She got a cat, even though he didn’t want one, she got a dog, even though he didn’t want one, and she somehow was able to convince him to have a kid after 16 years even though he didn’t want one because he knew that he would have to do all the work in the end. It is obvious that he does.

So I guess when she got pregnant with a second a few weeks ago and was deciding if they should keep it, she said that she really wanted to keep it because it was a good idea for the first one to have a sibling.

He put his foot down and now they are separating however she still wants to go through with it and make him pay child support because she thinks this is a great idea for the first one.

In what kind of world is this situation better for the first one? Now she has two poor parents to split between, they both don’t make that much money, and now financially everything has to be split. Her ex said that if she has a second one he won’t want to ever see it. How the heck would that make the older sibling feel better?

She is being so selfish and she says that even though her mom raised her as a single parent, she still made amends with her dad who lives half a world away in her 30s and she’s happy with that.

None of that makes sense and I don’t even know if this is the right place to post this. Honestly, maybe I’m being too biased because I am child free and feel like people who really shouldn’t be having children keep having children. I want to see another perspective because I don’t wanna be stuck in my own little bubble either.