Your dad's reaction is very admirable, because he is acting like a DAD!! I believe in open carry, my children believe in open carry, my wife, etc. etc. But, there would be butterflies in my stomach if I saw one of my kiddos open carrying the same way there were butterflies the first time I saw them ride a bike, drive a car, go to the gun range, and so on. Heck, I was nervous the first time my children (as adults) shared a cigar with me on our front porch. Remember, almost all dads have this "protectiveness" about their children no matter what age. My suggestion would be to attend a few open carry breakfasts, luncheons, and/or picnics, perhaps even coordinated by you. Then, you might want to ask your dad to come to one with you, and he could see the "typical" people who open carry. It may take a while to get your dad to grudgingly accept your choices, and he may never; but remember, nothing ventured, nothing gained. I strongly believe your dad will come around especially if you are patient ( I know this can be difficult) - One step at a time
I APOLOGIZE IF THIS SOUNDS LIKE I AM TALKING DOWN TO YOU - I AM NOT - I AM IMPRESSED THAT YOU ARE SHARING YOUR FEELINGS WITH US.