Is it true that cats don't die at home????

Last time I saw my cat was in a midnight about a week ago. She was kind of fishy lying on my bed. When I picked her up, I felt she was soft as cotton. Posioned was the first thing came up to my mind. I ran to my garden to cut some cactus and squeezed some juice out of it and try to feed her (I heard that could help). But when I went back to my room, she was gone. Then I thought she was might just relaxing and sleeping ealier. As the days past by (she’s never been out side more than a day), I felt she might be died. I heard that cats don’t die at home. When they know it’s time, they will always get away from home. Is that true? Why? I’d really like to understand them.