You have to accept fact that is not possible to inspire everybody about Bitcoin.
All of us have very different background, experience, understanding etc.
Some people feel very comfortable using Internet and trying new things and some people simple don't feel comfortable with new technologies.
I don't think that you can do much about it.
Even if you show your dad some good earnings from Bitcoin, he will still be skeptical, I guess.
Just focus on bitcoin and don't talk to much about it with people who can't understand it, otherwise you will loose to much energy on something what you can't solve.
but i think it also depend on you that how can you convince a person, if you have good skill of convincing, then it will easy for you to convince your father, it is also a fact that every one can different convincing capacity of understanding,