GPA dropped due to a death in the family. How do I explain this on graduate applications?
You haven't said what country you're in, and the answer may vary somewhat.  

From my experience in the US, I'd have concerns about an application with the kinds of grades you've described that didn't come with some explanation of the personal circumstances that caused the poor academic performance.  When I see bad grades with no explanation, I'll typically vote no on the applicant.  

However, even with an explanation of why you did poorly in the past, I'd also have to consider whether or not you'd be likely to do well in the future.  If the personal problems that you've had are ongoing, then it's likely that you'll continue to do poorly in your academic work, and you'd be a high risk applicant.  If the personal issues are well and truly resolved, then I'd be more likely to vote yes on your application.  

My advice would be to include a statement explaining your past poor academic performance, pointing out how you've done well at times when you weren't having these personal problems, and that you're confident that you won't have these problems going forward.  

If any of your recommendation letter writers can also address this, it might help too- many recommendation forms have a specific question asking the recommendation writer whether the student's grades are fully representative of their performance or whether special circumstances should be considered.  .  

You don't need to go too far into the details of your experience ("a family member died suddenly and I struggled with this during the xxx semester" is more than enough detail.)  What's more important is showing that when you aren't having such personal problems you have been a successful student and that these personal issues are no longer going to affect your academic performance.