Your dad's not stupid. I'm sure he understands the basics, if not a whole lot more, depending on what he does.
Being the last platform to embrace SSD's the Mac community is still in the honeymoon phase with SSD's. People are falling all over themselves in awe.
Don't get me wrong, they are certainly fast, I have SSD's in every Mac and Windows laptop I own. However due to the fact I've been using them in my ThinkPads for a lot longer, it's become routine for me. Like anything else I became used to them and now it's just normal. The "wow" factor is gone.
SSD's speed up boot times, shut down times, app launch times, and the times when the drive is accessed. However while working within apps, the difference is far less dramatic. In some cases there is no speed difference at all.
Finally, now that SSD's are optional on nearly every laptop made, there's little advantage across the board.