You've been asked this a million times

I can’t get Homebrew to load into Mohave. I’m not a developer, just trying to reset my son’s transmitter so I can read his blood sugar at school next week. I’m in over my head when using the terminal. I’ve been looking online for a fix for a few hours now and nothing has worked that I have tried. I get this following when I hit return after the initial install:

Press RETURN to continue or any other key to abort
==> /usr/bin/sudo /bin/mkdir -p /usr/local/bin /usr/local/etc /usr/local/include /usr/local/lib /usr/local/sbin /usr/local/share /usr/local/var /usr/local/opt /usr/local/share/zsh /usr/local/share/zsh/site-functions /usr/local/var/homebrew /usr/local/var/homebrew/linked /usr/local/Cellar /usr/local/Caskroom /usr/local/Homebrew /usr/local/Frameworks
sudo: /etc/sudoers is world writable
sudo: no valid sudoers sources found, quitting
sudo: unable to initialize policy plugin
Failed during: /usr/bin/sudo /bin/mkdir -p /usr/local/bin /usr/local/etc /usr/local/include /usr/local/lib /usr/local/sbin /usr/local/share /usr/local/var /usr/local/opt /usr/local/share/zsh /usr/local/share/zsh/site-functions /usr/local/var/homebrew /usr/local/var/homebrew/linked /usr/local/Cellar /usr/local/Caskroom /usr/local/Homebrew /usr/local/Frameworks
sudo: /etc/sudoers is world writable
sudo: no valid sudoers sources found, quitting
sudo: unable to initialize policy plugin

Holy cow, I got it to work! Thank you to whoever Ben Clifton is for giving such and easy solution. If anyone else is wondering what I did, he said to do the following.

“In all honesty, this problem was easy to fix for me. I went to etc/sudoers, right clicked it, hit Get info, and set it to “System : Read and write” and read only for everyone else. Then I did the same for sudoers.d. That fixed my issue.”