Just to shed further light on Mahler's 'obsession with death':  Mahler did
deal with feelings surrounding death in his music (as with life, love and
happiness), but not necessarily in a negative way.  Here's a quotation from
an essay by Donald Mitchell on the Kindertotenlieder

   "This might be the place, by the way, to clear up any misconceptions
   about a purely autobiographical interpretation of Kindertotenlieder.
   It is true that Mahler was to suffer the tragic loss of his elder
   daughter, but this was _after_ the song- cycle was composed.  Nor,
   as some commentators have implied, was there a morbid, unnatural
   preoccupation on Mahler's part with the death of children.  On the
   contrary, he transforms what might have been a topic too painful to
   dwell upon, into an experience that is ultimately ennobling and itself
   transcendent.  Even our sorrow at the loss of innocence, of lives
   intolerably abbreviated by the unpredictable and unforseen ...  can
   be accepted and, through acceptance, overcome:  the destruction caused
   by the 'storm' can be pacified and thus negated.  There is something
   almost Buddhist about the radiant resignation which Mahler's D major
   affirms at the conclusion of his finale:  it is a consideration that
   we shall have to look at again in the context of Das Lied [von der
   Erde]."

Ruben