['My dad knew I was having some financial difficulties and decided to pay off my car loan! I am so appreciative to him!', 'Wow, that was super nice of him. You are lucky to have such a great dad.', 'I really am!  I will do whatever I can to repay the kindness!']
That is a really great thing to hear. I hope you can find some way to pay back his kindness.
My dad knew I was having some financial difficulties and decided to pay off my car loan!  I am so appreciative to him!