There's one in the Character Sheets window (B) but I've never paid enough attention to it to notice it saying anything other than neutral so no idea if it works
Edit: Wait, there's an option in Divinity: OS2 to see your companions attitude? I don't think I ever saw that
It does work. If you use the dog petting exploit, you can see your status with Gale, Shadowheart and Wyll increase from/to neutral, medium, high, etc.
