I'm part of the category of those who think Brian is too suspicious to be the bad guy. Well... Maybe I'm the only one left in the category .
You're constantly pushed to be suspicious about him, but the one thing that is really overdone is the first time you speak to him as April. You actually have an option for responding in a cautious, suspecting way. I really thought at the time: "Why? Westhouse might have been a drunk at the time, but he helped April." And Why don't you have these options when Zoë speaks to so many people you don't need to trust (like Damien, I had the feeling he was pulling my leg there).
My main reason for believing in his innocence is that he is in league with Cortez.
And finally, for those who already condemn Westhouse: maybe he got some secret information out of Crow when he got him drunk in TLJ...