What is the ruling of Islamic Law on supplicating with other than the transmitted (Ma'thur) supplications in prayer?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
It is permissible to supplicate (make du'a) during the prayer for anything from the affairs of religion or worldly life, and the prayer is not invalidated by doing so.
Shaykh al-Islam, the Imam an-Nawawi, may Allah have mercy on him, says: "Our madhhab [i.e., the Shafi'i madhhab] holds that it is permissible for a person to supplicate during it [the prayer] with anything that is permissible to supplicate with outside the prayer, from the affairs of religion or worldly life. He may say: 'O Allah, grant me wholesome sustenance, offspring, a house, and a beautiful young wife' — describing her; or: 'O Allah, free so-and-so from prison,' or 'destroy so-and-so,' and other such things — and none of this invalidates his prayer according to us. And this is also the view of Malik, ath-Thawri, Abu Thawr, and Ishaq." [Al-Majmu', Vol.3/P.454]. And Allah, the Exalted, knows best.
What is the ruling on ablution if vaginal discharge is expelled, and is it impure?
If these discharges exit from the external genitalia (apparent part of the vagina), they are not impure and do not invalidate ablution. If they exit from the internal part, they are impure and do invalidate ablution. If it is uncertain whether they are from the internal or external part, they are not impure and do not invalidate ablution.
The apparent part is what becomes visible when sitting, and what the husband's penis reaches during intercourse is considered part of the apparent. The internal part is what is beyond that. And Allah the Almighty knows best.
What is the ruling of Islamic Law on one who died owing debts and left no wealth? Is it obligatory upon the heirs to settle these debts?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
The general rule is that if a person dies owing rights to other people, such as debts, these are settled from his estate, if he left any wealth, before the estate is divided. The Prophet (peace and blessings be upon him) said: “The believer's soul is suspended by his debt until it is settled for him.” Graded ḥasan by al-Tirmidhī. Repayment of debts takes precedence over the heirs’ right to inheritance.
If the deceased left no estate, or left wealth that was insufficient to cover his debts, it is not obligatory for the heirs to pay from their own wealth, but it is recommended for them to do so, because the deceased’s dhimmah (legal liability) remains occupied by the debt. It is reported in some narrations that he remains held in suspension until his debt is paid, and it is not part of filial righteousness for a child to leave his father’s dhimmah burdened with debt.
All of the children may contribute to settling the debt on behalf of their father and cooperate in doing so, even in installments, according to their ability. And Allah Almighty knows best.
Is it incumbent on a father to cover the marriage costs of his son if the latter couldn`t afford them?
The son should seek the help of his relatives in order to convince his father to do the aforesaid, and the father should make sure that his son doesn`t commit fornication through helping him to get married, and Allah will reward him for doing so.