As my pastor has told me innumerable times: “Everyone has doubts - even the most pious religious!”
You needn’t doubt God b/c we go through times of affliction - although it’s a perfectly natural way for one to react… Our God is so good that He draws us all the closer in our afflictions; He is not a stranger to suffering. He is right there at the cross - your cross and mine. I’m sure you know these things, but we are here to edify one another.
Life is so filled with suffering. Some people seem blessed with a life of ease and comfort while others seem to suffer continually, but I fear it is far easier to become complacent and unappreciative when life is filled with ease and consolation. The inevitable fact of life is that it is filled with pain - even for those who seem to escape hardship - b/c everyone endures sickness, the loss of loved ones, loneliness, etc… Look around the globe and there is immense suffering in other parts of the world - suffering we could not imagine enduring.
Suffering is very much a part of life, as is death, and we have a God that is not indifferent to it, and when we surrender ourselves to His Holy Will, there can be found joy immeasurable. “Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love him.”
Again, I don’t doubt you realize these things, but in moments of doubt it seems as though blinders come on, and the old nature takes the reigns…
My father in law died from cancer last July. We prayed fervently for his healing, and all were filled with such hope that it would happen - it seemed like signs were everywhere pointing to a healing for him. But he was not healed. I, on the other hand, was… I would have gladly lived the rest of my life with my ailment, but for some reason I was the one that received the healing. And I am certain that his healing would have had more far-reaching affects in this community than my own did. But I do not know that he did not experience spiritual healing - and that would be exceedingly more important than healing of his body.
I wouldn’t worry too much about having committed a serious sin, unless your doubt caused you to sin outwardly. It would be worth mentioning at confession the next time you go - or go sooner if it would bring you peace. You could also recommend yourself (and your mother) to the Lord at the hour of mercy. But know this: God is very close to your mother and your family right now. There was times we could just tell how present He was to our family when we went through my fil’s cancer. At times his home felt more like church than home.
Prayers for you and your mother and family - firstly, for the acceptance of God’s Will above all things, and for whatever outcome would save the most souls - particularly your mother’s and your own - and also bring the most glory to God.
Peace~
