Settling Debts Of Another As A Form Of Charity

The charity that we normally discharge is of two types. The first type is termed as Waajib Sadaqah (obligatory/compulsory charity) which includes inter alia, Zakaat, Sadaqatul Fitr (charity that is discharged on the occasion of the Eid-ul-Fitr), fulfilling the bequest of a deceased person by giving his money out in avenues of charity as indicated in his Will which will not exceed one third of the entire estate, fulfillment of a vow, for example. a student took a vow to give an x amount in charity if he passes his exams then discharging that particular amount in charity becomes Waajib on passing his examination, etc.

The second type of charity is termed as Sadaaqah-e-Nafila (optional charity). All forms of optional charity will fall in this category such as giving a beggar on the street, donating towards the expenses of a Masjid or Madrasah, providing for an orphan, etc. The charity that you are referring to in your question refers to Sadaaqah-e-Naafila where you are allocating a certain amount of money from your income for charitable purposes. This was the way adopted by our pious predecessors as well, where they would allocate a certain portion of their income for charity as a result of which they enjoyed plenty of Barakah in their earnings. 

Now coming to your query, if these funds are utilized in assisting your father to discharge his debts then this will fall under the category of Sadaaqah-e-Nafila (optional charity) and you will receive a double fold reward, reward of charity as well as joining family ties and fulfilling the need of your father. You should therefore assist your father in settling his debts without any sort of hesitation whatsoever.