To die

(Completely fiction. I hate the last two lines in the last stanza. please tell me what you think)

Look at you; so perfect,
My sister; my best friend,
You're dying and you're helpless...
So soon your life may end.

I'm sorry I can't help,
If I could I'd die for you,
Our blood-types don't quite match,
And your day's amount too few.

This cancer runs too deep,
You may not make it through the night,
I'm sorry I'm a failure,
Please don't go without a fight.

We already have the poison,
So, Lord, please send the cure,
You died in sleep on Sunday,
If only heaven weren't so sure.