Is the father a Mahram (Non-marriageable) to his son`s mother-in-law?
The father is a non-Mahram (Marriageable) to his son`s mother-in-law, so it is impermissible for them to look at each other, or to have a seclusion (Khalwah).
Can a woman leading other women in Tarawih prayer recite aloud?
Yes, a woman leading other women in Tarawih prayer is allowed to recite aloud, as long as no non-mahram (other than unmarriageable kin) men can hear her.
Is it required to fast consecutively when making up missed fasts?
● It is preferable to fast consecutively when making up missed fasts if they were missed due to a valid excuse.
● However, if the fasts were missed without a valid excuse, then fasting consecutively is obligatory, because making up the missed fasts in this case must be done immediately.
Separating the makeup fasts goes against the obligation of immediacy, but if someone does so, their fasts will still be valid. However, they will be sinful for delaying without a valid reason.
What is the ruling on performing dry ablution (tayammum) on a wall or stone?
One of the conditions for tayammum is that it be with pure, clean dust (soil). It is not valid to perform tayammum by striking stones, a wall, sand that has no dust (i.e., that does not produce dust), pebbles alone, or clay, as these are not from the earth or its same category. And Allah the Almighty knows best.