The Vietnamese word "cậy" can be understood in a few different contexts, primarily as a verb and also as a noun. Here's a breakdown to help you learn more about it:
Cậy anh đi giúp cho.
(I rely on you to help me.)
Trẻ cậy cha, già cậy con.
(When young, one relies on one's father; when old, one relies on one's children.)
This saying highlights the dependence people have on their family members at different stages of life.