My sister died of cancer after a painful time - catholics in the family said she was in hell as she did not go to mass and was not a practising catholic. I find this side of the church abhorrent and cruel. No one is going to hell. There is no hell.
That is heresy, and belief that there is no hell is a sign that one is headed towards perdition. I am sorry to say this, and I believe we are all called to heaven, but to say there is no hell is to be headed there.
Nobody in this life can tell whether or not someone is in Hell. This is up to God. And up to your sister, because ultimately it all boils down to whether or not she truly willfully and deliberately rejected God. As for you, your duty is to pray for her and to not make the same mistakes she may have made. You do not want your wife or kids tomorrow to be afraid that you are in hell, or to despise the Church and be lost themselves because of this.
Illness is a profound mystery that configures a person with Christ to extents that nobody can know in this life. This is especially true for an illness like cancer. I know it because it affects one of my loved ones.
St. John Chrysostom, Father of the Church, used to say that the Lord preached more often on the Catholic Dogma of Hell than any other subject. In fact, the Lord speaks of hell much more than he speaks of heaven. Meditation on damnation and hell produces many fruits of conversion and stirs our love for God and for devotion. When we meditate on Hell we become holy.
The plot of Satan, the most cunning adversary, a true genius in fact, is to hide his existence and to deceive even us, Christians, to believe that there is no divine justice, no eternal punishment for those who reject God, and thus to reject the very idea of hell…along with concern for sin! Because if there is no Hell, then there is no need to be concerned with sin, or rather, of repentance from sins, and of doing God’s will.
A great mystic, Sr. Josefa Menendez wrote in her “Way of Divine Love” a vision of hell she had. She saw a soul who had just arrived, cursing those who had not taught her to fear God nor that there was a Hell. The great Doctor of the Church s. Teresa of Avila, after a vision of hell, said: “
This also makes me wish that, in a matter which concerns us so much, we did not rest satisfied with doing less than we can do on our part – that we left nothing undone.”.
It is good, in fact our duty, to pray for our loved ones and to not judge them the way the world judges - oh, x never went to Mass, what a sinner, he’s probably in hell. That in fact can bring judgment upon ourselves, for “by the judgment with which we judge, we shall be judged.” No, a person who lacks full knowledge or deliberate consent about the obligation of Sunday Mass is not guilty of mortal sin at all - and even if he were, repentance on deathbed is more than sufficient to obtain full remission of all mortal sin and ensure salvation. God is good, and no unfairness is found in him.