Is the saying: "May my father and mother be ransomed for you" considered swearing by other than Allah? And what is the meaning of "May your mother be bereaved of you"?

"By my father and my mother, you are ransomed" is an expression of reverence and respect, not a legal oath. "May your mother be bereaved of you" means "may you be lost to your mother," and it is an invocation of death not intended to occur, but rather for admonition, to awaken one from heedlessness, and to emphasize the gravity of the matter.