One you can say to your father is, you can tell him bitcoin is a new commodity to trade or to save to earn more money. It's a new kind of investment.
Yes using technical terms usually scares the person and there is a possibility that the concerned person might stay away from the thing we want him to know.
So, It would be great to use very familiar language and explain bitcoin technology with some familiar terms like email, sms, etc. As per my experience, demonstration works smoothly while explaining bitcoin to a new person and giving him some satoshis in his fresh wallet is like turning a key for starting his car.