My father placed shares worth twenty dinars in one of the banks, and their value doubled to become five thousand dinars. When my father passed away, one of the scholars told us that it is permissible for us to take the money. What is the ruling on this money, considering that it comes from a bank and involves interest (Riba)?
Allah The Almighty Said (What means): "And if you repent, then for you is the principal of your wealth. You do not wrong, nor are you wronged." [Al-Baqarah/279]. This is the precautionary ruling regarding what you are asking about. You are entitled to the principal amount, and you should give the excess as charity to the poor and needy. If you are poor, you may take from it. And Allah The Almighty Knows Best.
If someone bought a car from an interest-based bank and then sold it to another person, does the second person bear any sin if they use the car's price to pay the installments owed to the bank?
When the buyer purchased the car, it became their property, and the price became their responsibility. The bank acts as the seller's agent for receiving the payment. Therefore, there is no sin on the second buyer, God willing, as long as the bank does not impose an increase in the amount if a payment is delayed. And Allah The Almighty Knows Best.
What should one who made an intention, at night, to make up for a missed fasting day, but broke his fast on the next day?
One who started making up a missed fasting day, then broke his/her fast without a legitimate reason is considered sinful, and is only obliged to make up for the missed fasting days. And Allah Knows Best.
What is the ruling on training dogs that are of benefit?
All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
This is permissible because Allah The Almighty Says (What means): "They ask thee what is lawful to them (as food). Say: lawful unto you are (all) things good and pure: and what ye have taught your trained hunting animals (to catch) in the manner directed to you by Allah. eat what they catch for you, but pronounce the name of Allah over it: and fear Allah. for Allah is swift in taking account." [Al-Ma`idah/4]. However, it is prohibited to keep dogs for no benefit because Salim reported on the authority of his father that Allah's Apostle (PBUH) said: "He who kept a dog other than one meant for hunting or for watching the herd, lost two qirat of his reward every day." [Moslim]. And Allah The Almighty Knows Best.