Is your mother obligated to fulfill a vow she made without knowing its basis or reason, merely imitating another woman, considering that she is non-Arab, illiterate, and does not know much about religious matters?

If the mother does not know the meaning of a vow (nadhr) and its implications, then she is excused due to her ignorance, and nothing is binding upon her. However, if she does know the meaning of a vow, then the type of her vow should be considered. If it was a vow of obedience, she must fulfill it; if she is unable to, she must offer an expiation for an oath (kaffarat yamin). If it was a vow of obstinacy (nadhr lajaj), which is to prevent oneself from something or to urge oneself to something, she has the choice between doing what she vowed or offering an expiation for an oath. If it was a vow to perform a permissible act, she has the choice between performing it or offering an expiation for an oath.