well, if it was water I'd agree but root beer might be conductive even when it dries out. He really needs to clean it off any circuit board traces with some kind of contact cleaner before powering it up IF any got in there. So at the least he should pop the top and look in there just to see ...... just don't go shoving your hands in there..
First ..... was it running when he spilled the root beer?
If it was not on then it's not damaged. Root beer isn't gonna immediately eat away components or dissolve traces or anything so if it wasn't powered up then there's no damage to assess.
IF it was on then my question would be did it continue to operate normally?
If so then again there's no damage.
I'd pop that sucker open and check to see if there's any residue on anything and clean the crap outta any I saw with DeOxit but any contact cleaner or even alcohol will work.
Those big can shaped things in there? Don't stick your tongue or any other part of your body on them.
If there's no residue other than on the chassis then do nothing ..... close it back up and you're fine.
IF there's root beer on circuits then IF you can easily get to them without getting near the big caps carefully clean it off.
If it's close enough to the caps where you don't think you can avoid touching them you'll need to drain them with a resistor and wire.
There's plenty of tutorials on how to do it ...... it's not hard and the dangers, while they exist, tend to be overstated in this nanny sort of world. You definitely don't want to get bit ..... believe me ..... it hurts and will also probably make you jerk your hand back so hard you'll bang it into something or even your face!
But I find it unlikely that any competent person could electrocute hisself simply by opening up the cab to see if any rootbeer got in.