What is the ruling on the intention of fasting, where is its place, and when is its time?
The intention is a pillar of acts of worship; it is essential, and worship is not valid without it.
Its place is in the heart, and verbalizing it is recommended so that the tongue reminds the heart. Its meaning is to be determined to abstain from nullifiers of fasting during the upcoming day with the intention of worship and obedience to Allah Almighty. This meaning is naturally present in every Muslim on every night of Ramadan, so there is no need for obsessive doubts. If one says, "I intend to fast tomorrow for the sake of Allah," it removes any doubts.
Its time is from after sunset until before the true dawn.
Should one who doesn`t perform prayer out of laziness make it up later, and how should he/she do so?
All perfect praise be to Allah,The Lord of The Worlds He/she is obliged to make up missed prayers by offering with each obligatory prayer another one, and if he/she offers two, then it is better. And Allah Knows Best.
My father has debts and asked me to repay them years ago, and I promised him I would do so upon his death — is it permissible for me to go back on my promise given that I am unable to repay them, especially since he refuses to contribute to repayment on the grounds that the debt has become my responsibility by virtue of my promise?
All praise is due to Allah, and peace and blessings be upon our master the Messenger of Allah ﷺ.
The established principle is that a father's debt is to be repaid from his own wealth, if he possesses sufficient means. As for the promise made by the son to repay it on his father's behalf, fulfilling such a promise is strongly recommended, and breaking it is considerably disliked. Shaykh al-Islām Imām al-Nawawī, may Allah have mercy upon him, states: "Fulfilling a promise is emphatically recommended, and breaking it is severely disliked. The evidences for this from the Qurʾān and the Sunnah are well known." [Rawḍat al-Ṭālibīn,Vol. 2/P.278] Shaykh al-Islām Imām Zakariyyā al-Anṣārī, may Allah have mercy upon him, further states: "The reason fulfilling a promise is not obligatory and breaking it is not forbidden is that a promise is in the nature of a gift, and a gift does not become binding except upon receipt." [Asnā al-Maṭālib fī Sharḥ Rawḍ al-Ṭālib,Vol. 2/P.487]
Given that the son does not possess the financial means to fulfil his promise to his father, breaking this promise falls beyond his capacity — and Allah does not burden a soul beyond what it can bear. Since the father himself possesses sufficient wealth to settle his own debt, repayment must be made from his own funds. Should he pass away before doing so, the debt is to be settled from his estate. And Allah the Almighty knows best.
What should one do if they see someone deliberately eating or drinking openly during Ramadan?
They must enjoin what is right and forbid what is wrong. If they fear harm from that person, they should disapprove of it in their heart but avoid sitting with them if possible. It is also preferable to seek the help of the authorities to prevent them from doing so.