Is it permissible for my mother to perform the prostration of forgetfulness (sujud al-sahw) after every prayer, thinking that it compensates for the lack of devotion and wandering thoughts during it?

Prostrations of forgetfulness (sujud al-sahw) after every prayer is an impermissible act. The questioner should clarify to his mother that this is what the scholars have affirmed, and that her prayer may become invalid if she adds prostrations intentionally and impermissibly. Sujud al-sahw is not prescribed for a deficiency in humility (khushu'). If the mother is afflicted with excessive doubts, some scholars have deemed it commendable for her to prostrate after the salām to vex Satan. However, many scholars do not consider sujud al-sahw permissible for someone afflicted with obsessive doubts (waswas).