死後 is read as しご (shigo) and means after death.
しご
shigo
いっしご
after one out
にしご
after two outs
しごこうちょく
rigor mortis
しにん
corpse
したい
dead body
ししゃ
dead person
しきょ
death
しぬ
to cease
しせい
life and death
dead language
し
(an) out
しにたい
hopeless situation