If your mother is ill, it's called love, not cancer. Because of the inseparable love between you two, you always worry about her health and subconsciously worry about her. An unbearable pain threatens you and becomes a dream.
So, don't worry, as for the scene in the dream, it's just a fusion of memories, and there have been so many TV movies. If you really want to find a way to interpret dreams, open a duke of Zhou, dream of a coffin and get rich; Dream of the dead, good luck; Dream of water, good luck.
I also reminded myself to honor my parents, and don't wait until "children have to be raised and relatives don't wait" to regret it.