To one who has suffered the unexpected loss of a loved one, one of the worst things you can say in an effort to comfort is: "It must have been his time." Basically, this is assigning the responsibility of the untimely end to God, who is, in the Christian world, love! And by the way, you are supposed to turn to this same God for strength in your time of need. Thanks a lot! I have been there, and I know how it feels. It makes no sense, and if anything, it increases the painful feeling.
Sometimes, the right thing is to confirm that the untimely loss was a terriby unjust thing - it should never have happened, etc. Then proceed with the reassurance that God would never leave the victim alone, for he belongs to God, his life is God. Of course, there is no formula for what to say at a time like this, and it must come from the heart - otherwise silent loving is preferable!
A little background would help. First, if we consider how conception comes about, how void of moral substance is the physics of it, we will recognize there is no moral justice preventing the unwanted child, the deformed child, the child of poverty, etc. So should we be surprised that there is no moral justice governing the termination of mortal existence? Mary Baker Eddy refers to the whole thing as "the ghastly farce of material existence." The Bible explains it in the story of Adam - created out of dust, set up to fail, and then is cursed for failing. This is not a God I want to have anything to do with!!
However, Genesis 1 presents the much more consistent creation of a God who is love, which includes man, His image and likeness, etc. - ALL good, complete, and no place for anything bad! It is safe to say that this creation is spiritual, for only such could be free of "sin." In the New Testamant, Paul aligns this spiritual creation with Christ: "For as in Adam all die, even so in Christ shall all be made alive."
Upon this platform the following is offered:
"Life is real, and death is the illusion. A demonstration of the facts of Soul in Jesus' way resolves the dark visions of material sense into harmony and immortality. Man's privilege at this supreme moment is to prove the words of our Master: 'If a man keep my saying, he shall never see death.' To divest thought of false trusts and material evidences in order that the spiritual facts of being may appear, — this is the great attainment by means of which we shall sweep away the false and give place to the true. Thus we may establish in truth the temple, or body, 'whose builder and maker is God.'" (S&H)
From this standpoint, one is much more able to meet the need of the sufferer who has lost a loved one, not with words, but with a quiet assurance that a good God is present, and that the lost one is not lost to Him.