Maybe the best thing to tell your father is GoldCoin and other currencies are like stocks and commodities, more like commodities. Yes it can be risky but you won't be out much other than the power to run everything and the cost of the video card(s).
Myself I don't even think about my electric bill. I get one every month anyway so it's no big deal, I just pay it. I'm not into adding up every penny like whats this cost, whats that cost, breakeven point etc.. Just do it. Yes it's good to know but really who cares? Unless your a business in it for profits right now. You either like the coin your mining or move on if the profit isn't there for you.
Some people think all the coins are a scam, not all of them are. I can't say for sure which ones are and which ones aren't. I've been with GoldCoin almost from the start. It has had it problems and the new Dev team is doing everything it can.
I would bet your father is younger than I am and trust me I thought all of this was some kind of joke until I started watching the value of the coins and doing a lot of reading and I found out I could mine them, slow as it maybe and now I have a few dollars in value just from playing around. Look at GoldCoin a few weeks ago you could get them for a half a cent each and now they are around 10 cents each. Your dad should understand that part of it. Just like a stock buy low sell high. Right now GoldCoin is buy and hold.
You can even have him look on Forbes
http://www.forbes.com/sites/reuvencohen/2013/11/27/the-top-30-crypto-currency-market-capitalizations-in-one-place/ GoldCoin is on that page. I don't think Forbes is going to talk about different coins in a good way if they thought it was all one big scam.
You need to get your dad into it with you. Show him different prices of the coins. Mine some and show him what you can make.
Use
http://preev.com/ it gives you BTC = USD and use this page for GLD = USD
http://gld.skillerzforum.comUse Cryptsy to find out how much BTC you can get for your coins and use the page to get a BTC = USD dollar amount. Then use the other page for GLD = USD. He'll start to understand how it works.
Just have your father do it with you and have him ask some questions. I'm sure the members will be willing to help in anyway they can.
He can't really lose anything other than a few dollars. I bet he might spend more on coffee each month. Plus there's an upside he'll get to learn about something new and help you at the same time.
So you and your dad can mine, make a few dollars (I hope) learn something and spend time with each other and best of all you'll get mad at each other

I know that will happen LOL It's a family thing you just can't help it. But it'll workout in the end and I bet he'll smile from ear to ear.
Now that I wrote a book. Tell him he can ask questions on the forum.