All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu 'alayhi wa sallam, is His slave and Messenger.
When your father’s wealth reaches the Nisab (the minimum sum on which Zakah is due) and a Hawl (full lunar year) passes since the wealth reached its Nisab, he must pay Zakah on it, including any debts owed to him - such as the money he has lent to you.
The method of paying Zakah on a debt depends on the debtor’s situation (in this case, you). If the debtor is solvent, acknowledges the debt, and is not denying it; your father should include it in his Zakah calculation every year when the Hawl passes.
If the debtor is insolvent or procrastinates in the payment, your father should pay Zakah on it for one year only when he actually collects it, even if it has been owed (by you) for years.
Furthermore, the money you have received from your father counts as a debt you owe him.
We remind the questioner that taking someone else’s money - even he is your father - without his verbal or implied permission (according customary practices) is not allowed, as stated in the Hadith: “The wealth of a Muslim is not lawful except by his free consent.” [Al-Bayhaqi]
Hence, if you took the money without your father’s permission, you must repent to Allah and return the money immediately. You do not have to tell him what happened; what is required is to return it as soon as possible. If you cannot return it all at once, you should repay it in instalments according to your ability, as Allah says: {Fear Allah as much as you can} [Quran 64:16]. The Prophet, sallallahu 'alayhi wa sallam, also said: “The hand remains accountable for what it takes until it gives it back.” [Ahmad]
If you borrowed the money with your father’s permission with the intention to return it, then it is a loan that becomes a part of your property while you are using it.
Since you have used it as you have mentioned in your question, then there is no reason to pay Zakah on it. However, if you have other wealth that is subject to Zakah, you can subtract from it the amount you owe others including what you owe your father as a loan or else. Then, if the remaining wealth reaches the Nisab, you have to pay Zakah on that remainder; if it does not, no Zakah is required.
For more details, see Fatwa 324727.
Allah knows best.