I can`t afford to get married, what should I do to curb my sexual drives?
You should offer a lot of voluntary fasting, keep busy with useful and permissible acts and make supplication to Allah, The Exalted.
What is the ruling of Islamic Law on leaving the Sunnah prayer of Dhuhr due to fatigue?
Praise be to Allah, and peace and blessings upon our master, the Messenger of Allah.
According to the general rule, a Muslim should strive to maintain the Sunnah prayers before and after the obligatory prayers (al-sunan al-qabliyyah wa al-ba'diyyah). One is permitted to pray them sitting from the outset, but if one leaves them due to severe fatigue, there is no objection to doing so. It is recommended (mustahabb) to make up (qadā') a time-bound supererogatory prayer (nafl mu'aqqat) at any time if it was missed.
Al-Shirbīnī (may Allah have mercy on him) said: "If a time-bound supererogatory prayer is missed, it is recommended to make it up according to the more authoritative view (al-azhar), based on the hadith recorded in the two Ṣaḥīḥs: 'Whoever sleeps through a prayer or forgets it should pray it when he remembers it.' This is also supported by the fact that the Prophet (peace and blessings be upon him) made up the two rak'ahs of Fajr when he and his companions overslept in the valley and missed the dawn prayer until the sun had risen [narrated by Abū Dāwūd with an authentic chain]." And Allah, the Most High, knows best.
What should a person who doubted having missed a pillar of prayer do?
All praise be to Allah, The Lord of The Worlds. The prayer of one who doubts having missed one of its pillars is valid, and nothing is due on him/her since having a doubt after offering the act of worship doesn`t undermine its validity. And Allah Knows Best.
What is the ruling on giving the expiation of an oath (Kaffarat al-Yamin) to a charity that feeds the poor?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
It is allowed for a Muslim to appoint a proxy (agent) to distribute the expiation (Kaffarah) on their behalf. Our jurists have explicitly stated the permissibility of delegation (Tawkil) in the distribution of Zakat, Kaffarah, and vows (Nadr).
It is stated in Mughni al-Muhtaj (Vol.3/P.237): 'One has the right to pay the Zakat of their wealth personally... and they also have the right to delegate it.' And Allah the Exalted knows best.