There are a few versions of God seeing that someone's tired and too ill to carry on, but they are no doubt too overtly religious for your mum's requirements. I've taken the liberty of "secularising" the poem, in the hope that it might meet your mum's needs a little better.
We saw you getting tired,
the cure was not to be.
We wrapped you in our loving arms
and whispered "Time to leave."
You suffered much in silence,
your spirit did not bend.
You faced your pain with courage
until the very end.
You tried so hard to stay with us,
your fight was all in vain.
We took you in our loving arms
and wished you free from pain.
A golden heart stopped beating,
two loving hands at rest.
We could not have to stay with us
To be at peace was best.
It's lonely here without you
We miss you more each day
Life doesn't seem the same
Since you've gone away.
When days are sad and lonely
And everything goes wrong
We seem to hear you whisper
'Cheer up and carry on.'
Each time we see your picture
You seem to smile and say
'Don't cry, I'm not so far away
We'll meet again someday.'
Since most sites say author unknown, I hope no-one feels it's inappropriate to adjust the words in this way.