What is the ruling on lying to one's mother and swearing to it for fear of her punishment and her ill opinion, knowing that this has happened repeatedly?

It is obligatory to attend to the prayer and to make it up immediately upon remembering it, if it was forgotten.

One must repent to Allah for lying and for the false oath. There is no expiation (kaffarah) for a false oath, although some scholars deem it obligatory as a precaution. This expiation involves: feeding ten needy persons, or clothing them, or freeing a slave. If one cannot find [the means], then fasting for three days. Allah Almighty says: "So its expiation is the feeding of ten needy persons from the average of that which you feed your [own] families or clothing them or the freeing of a slave. But he who finds not [the means to do so] - then a fast of three days. That is the expiation for oaths when you have sworn. And guard your oaths. Thus does Allah make clear to you His verses that you may be grateful."