brave browser suddenly keeps crashing on open.

It could be a corrupt profile within the Brave browser. There is a way to launch Chromium based browsers using a different browser profile, but I don't think I've ever done that on macOS (I did do it years ago on my Linux system as it involved invoking a command line option flag when launching the browser IIRC). I have since configured my Chromium based browser (Vivaldi) to always open to a profile selection screen to make troubleshooting such issues easier. Surprisingly, I also have never had a corrupt browser profile since....go figure.

The OP has the last compatible version of Brave installed on macOS Mojave 10.14.6. Your link is for a current version of Brave that is not supported on the older release of macOS. To reinstall 1.57.64, one must visit this page, from where one is directed to get the correct Brave version for Mojave.

Skateparkpiracy wrote:

what can happen if sip is not active?

This is a real world example of an accidental issue with a Google Chrome update, imagine if someone had bad intentions instead:

https://arstechnica.com/information-technology/2019/09/no-it-wasnt-a-virus-it-was-chrome-that-stopped-macs-from-booting/

I see you have System Integrity Protection disabled, which is a bad idea. You should re-enable that.

Disabling and Enabling System Integrity Protection | Apple Developer Documentation

If a simple reboot of your Mac doesn’t fix things, see if the problem still happens in safe mode.  Use a wired USB keyboard for this. If you have the Magic Keyboard, plug that into the Mac with its charging cable.

How to use safe mode on your Mac - Apple Support 

Safe mode will often correct weird software behavior by forcing the OS to clear caches, do disk repair and other self-maintenance and housekeeping and temporarily disables third-party mods.

Does Brave still crash while in Safe mode?

You can exit safe mode by restarting your Mac normally, then reevaluate the problem.

If the above doesn't solve the problem, then this:

Uninstall the Brave app: https://support.brave.com/hc/en-us/articles/4404876135565-How-do-I-uninstall-Brave

Then download a fresh copy of the app and reinstall. https://brave.com/download/

so i had to open brave - turn off the ad block features then i could open up youtube or google.

I had to do something similar with a different website. Brave wouldn't crash, but the page was completely unresponsive.