How to answer “Why is graduate study important at this time in your life?”, when the reasons are very personal?
You should probably keep your academic interests as the main point. If you write that you are applying to recover from a tragedy in your life, it might not be clear whether you are actually interested in that specific program (or are you just looking for something to do) or whether you might change your mind later.

Also, someone could suspect whether you could tolerate additional stress right now.

Anyway, if you have been out of work or study for a long time due to the tragedy, it is probably best to briefly mention it.