Having a Hard Time

First off, I want to wish Dad a Happy Birthday. He turns 50 today. But it doesn't end there. He is having a hard time accepting the age. The past couple of days, his mood has been gloomy and he just seems down right depressed. Last night, when he came home from work, I finally figured out because he doesn't want to turn 50.

I know no one wants to turn 50. Heck, I'm only 3 years away from turning 30 and I'm terrified. And I understand why he doesn't want to turn 50. It's a scary number for anyone. He wishes he could have done more with his life. He feels as if life has suddenly caught up with him and "Where did the time go"? His daughters are doing their own thing, leaving him feeling... well, old.

How do I know all of this? Besides being aware of my Dad's feelings, whether he says them or not, he told Mom how he felt. She knows exactly what he's going through, having been through it herself. I personally don't have any words of wisdom for him. I wish I could make him see that he still has tons of life left in him. Does anyone have any ideas of how to make him feel as if 50 isn't the last number in birthdays?