Many years ago I stole money from my father.

Answer

The only thing you have to do is to inform your father, seek forgiveness and arrange to pay back. If you humbly seek forgiveness from him and Allah Ta'ala, your father will in all probability forgive you and not ask for repayment. If you do not do so, you will be accountable in the Aakhirah where Jahannam may be the recompense for your exceptionally evil sin of having been so treacherous to your father.