Welcome to the post! You asked a great question and you are correct. Your brother needs to cast as many rods as he can before making a decision. Everyone has different casting styles and preferences. From a personal perspective, I love Winston rods. I don't think they get enough attention when people ask about rods on forums, but they are expensive. To be a little more specific, I tend to prefer Sage rods in heavier weights and Winston in lighter weights. When choosing a 3 wt, I did try the ZXL and loved it, but when I tried the Winston Biit, I loved that one even more. You can't go wrong with either rod, but for me, the Biit has a little more "oomph" for casting into wind (not that you need much for where I use a 3 wt), but I also just liked the feel of the Winston in my hand and the way it responded to different types of casts. I also have a Biix in a 4 wt. I preferred the Biit for a 3 wt b/c I wanted a slightly slower casting rod for the streams/fish/conditions where I use the 3 wt. Again, these are just my personal preferences.
If your brother hasn't already been there, have him check out the Winston forum. There have been numerous discussions about the differences b/w the various Winston rods. http://www.winstonrods.com/forum/