What is the ruling on the follower`s prayer if the Imam stands for a fifth rak`ah?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
If the Imam stands up for an extra unit (rak‘ah) of prayer out of forgetfulness, he must return to the sitting position as soon as he remembers, and he should perform the prostration of forgetfulness (Sujud al-Sahw). It is the duty of the congregants (Ma’mumin) behind him to remind him. However, if the Imam is in a state of doubt regarding the extra unit (and not certainty), it is not permissible for him to return.
As for the congregants: anyone who is certain that the Imam has stood for an extra unit is forbidden from following him. In this case, the follower has two choices: either intend to separate from the Imam (Mufaraqah) and finish the prayer alone, or wait for the Imam in the sitting position and perform the final salams with him—the latter being the preferred option. If a follower knowingly follows the Imam into an extra unit, their prayer becomes invalid. However, if a follower is in doubt and not certain of the mistake, they must continue following the Imam, as the Imam was appointed to be followed.
It is stated in Al-Majmu’ (Vol.4/P.145): 'If [the Imam] stands for a fifth rak‘ah, the follower should not follow him, even if it is assumed that the Imam might have omitted a pillar from a previous unit; because if the reality is known, following him is impermissible since the follower has certainly completed their own prayer. Even if the follower had missed a previous unit (Masbuq) or was in doubt about performing a pillar like the Fatihah, and the Imam stood for the fifth, it is not permissible for the latecomer to follow him in it. This is because we know that this unit is not counted for the Imam and that he is mistaken in performing it.' And Allah the Exalted knows best.
Can someone who begins a voluntary fast break it?
It is preferable for someone who begins an act of worship not to break it.
Allah the Exalted has said {what means}: "and let not your [good] deeds come to nought!" [Muhammad/33].
However, if a person starts a voluntary fast (nafl) and needs to break it, they are going against what is preferable, but there is no sin upon them.
What is the ruling on the fasting of a woman who has reached menopause if menstrual blood flows?
If a woman reaches the age of menopause (which is usually sixty-two) and her menses have ceased, then she sees blood after that, and its duration is not less than a day and a night (24 hours), it is menstruation (hayd). If it is less than a day and a night, she is considered as having non-menstrual vaginal bleeding (mustahada), so she fasts and prays. However, she must perform ablution for every obligatory prayer after its time enters, pray immediately, and be treated as a person with a continuous condition. There is no specific end limit for a woman's menstruation; it is possible as long as the woman is alive. And Allah the Almighty knows best.
Is it permissible for a woman to observe voluntary fast without her husband's permission?
A woman is not permitted to observe a voluntary fast (nafl) while her husband is present without his permission.