Here's how you can respond, depending on the context and your relationship with the person asking:
Formal:
* Mi papá es muy amable y cariñoso. (My father is very kind and loving.)
* Es un hombre trabajador y dedicado a su familia. (He is a hard-working man and dedicated to his family.)
* Es un buen hombre. (He is a good man.)
Informal:
* Mi papá es un poco loco, pero lo quiero mucho. (My dad is a little crazy, but I love him a lot.)
* Es divertido y siempre nos hace reír. (He's fun and always makes us laugh.)
* Es el mejor papá del mundo. (He's the best dad in the world.)
If you don't know your father well or don't want to share details:
* No lo conozco muy bien. (I don't know him very well.)
* No me gusta hablar de mi familia. (I don't like to talk about my family.)
Remember to adjust your response based on your relationship with the person asking and your comfort level sharing information.