One of the problems with taking off for any period of time more than a day or two is that it rarely fits in the real world of a baseball player. If there aren't games, there are practices or lessons.
I think each case is unique. JetsR71's first reply has a lot of good sequence info. If your player has a hitting instructor or primary hitting coach, he should be able to help him take steps to analyze the situation and give him direction based specifically on what he is seeing or hearing.
It is my experience that most hitters who enter a cage session looking to find something specific will do so. Or, at least, they will make some minor change that has them thinking differently, more confident and mentally prepared to step in the box next game. Guidance from an eye they trust usually increases the chances of finding something helpful. Often, it can be mechanical. Often, a slight variance to the AB approach will do the trick.