If you meant you lose track of him during fights, click on his party bar to highlight him (both on compass and on screen), or use ALT. Other than that you'll just have to pay attention to the bodies and tell him by the armor.
Perhaps zooming in/out will help (mouse scroll), also try rotating perspective. You can also try painting his armor (or just his helmet/mask) a certain color (not sure how well this will go down with him though

). You can also customize size and position for everything on the screen and put it places you think will help you see them better (see the options; no worries you'll break stuff, you can reset it anytime you want).
I'll grant you that it can be confusing to keep track of someone (let alone everybody) during a fight (maybe there's an option to always show the green labels?)
You will get used to it eventually, it's like when you're learning to drive and they tell you you have to look at all the mirrors and in front of you at the same time and you tend to take it literally.

But it's just a matter of training to follow several things at once "in the background".
I can tell you that you
will have to learn to do this, if you want to get any good then any class you play has to be aware of the entire battlefield at any given time to some extent. Some more than others (monks in particular need to cover
everything all the time). On the other hand, don't kill yourself trying, it comes naturally with practice.