What should a child do if he sees his mother committing adultery?

Whoever witnesses a reprehensible act committed by his mother or anyone else must strive to change it with whatever means he can, in accordance with the general saying of the Prophet, peace be upon him: "Whoever among you sees a reprehensible act, let him change it..." This must be done in a way that does not result in a greater harm than the harm of remaining silent about the reprehensible act. Preventing one's mother from sins is considered an act of righteousness and kindness towards her.