Is it permissible for a guardian (Big brother) to unlawfully stop his sister from getting married?
If the guardian denies her right in getting married for an unlawful reason, she should go to court in order to settle that matter, and the guardian is considered sinful in this case.
Is the one who gives up on marriage because he can`t afford it considered sinful?
Marriage is desirable, but one who can`t afford it isn`t considered sinful. However, he should supplicate to Allah, and seek His forgiveness.
What is the ruling on giving Zakat al-Fitr in cash?
The default ruling is that Zakat al-Fitr should be given as the staple food of the land. In Jordan, for example, the staple food is wheat or rice, and the amount of Zakat al-Fitr is 2,500 grams per person. It is easy to give this amount of rice to the poor and needy, and this is the correct ruling according to all Islamic schools of thought.
However, Hanafi scholars have permitted giving Zakat al-Fitr as monetary value, considering it more beneficial for the poor and easier for the giver.
Which is better during the day in Ramadan: reciting the Quran or performing voluntary prayers?
A Muslim should establish a daily schedule for reciting the Quran in Ramadan.
Once they have completed their daily portion (known as a wird or hizb), they can engage in other acts of worship, including voluntary prayers (nawafil). Prayer itself is called "Quran", because a significant part of it involves reciting the Quran.
Allah says: "BE CONSTANT in [thy] prayer from the time when the sun has passed its zenith till the darkness of night, and [be ever mindful of its] recitation at dawn: for, behold, the recitation [of prayer] at dawn is indeed witnessed [by all that is holy]." [Al-Isra`/78]