I'm so sorry to hear that you lost your mom to cancer. My wife recently lost her mom to cancer as well. But what helped us to deal with her loss is what we learned about God from the Bible. For example, he shows that he is not to blame for the suffering people undergo today. I know you may have heard some people say: God won't put on you more than you can bear. But that is not what the Bible says. This is what the verse they think they are quoting from the Bible really says:
1 Corinthians 10:13 No temptation has come upon you except what is common to men. But God is faithful, and he will not let you be tempted beyond what you can bear, but along with the temptation he will also make the way out so that you may be able to endure it.
Note that the verse says "He will not let you be tempted beyond what you can bear." In saying he will not let you be tempted, he makes it clear that he is not the source of the temptation or trial. But that someone else is harassing us. The Bible identifies this harasser to be Satan the devil. He is primarily responsible for the suffering we experience. But he also endeavors to shift the blame on to God in an effort to get us to blame God for our pain, when all the while it is Satan himself who is responsible. Consider how the Bible reveals this by reading Job 1:6-12 and Job 2:3-7.
Jehovah God further clarifies that he is not the cause of our suffering at James 1:13 where he says:
"When under trial, let no one say: “I am being tried by God.” For with evil things God cannot be tried, nor does he himself try anyone."
Yes, Jehovah God is not the cause of suffering. And happily he reveals how he is going to reverse all of the bad things that have happened on this earth. Revelation 21:3, 4 reveals this wonderful promise:
"3 With that I heard a loud voice from the throne say: “Look! The tent of God is with mankind, and he will reside with them, and they will be his people. And God himself will be with them. 4 And he will wipe out every tear from their eyes, and death will be no more, neither will mourning nor outcry nor pain be anymore. The former things have passed away.”
May what Jehovah has promised to accomplish through his dear son, The Lord Jesus Christ, bring comfort to you.