This post of yours is very interesting. I deal a lot with helping people find their own purpose. And I have found that in this day and age when people live much longer people tend to ask this question more when they reach retirement age. So there is hope for your friends yet! There are only so many tv episodes a person can watch after all.
You are a very lucky person to have a mission already and you definitely inspire those around you just by your actions. I have always admired young people who have a seemingly ready made maturity about life which I am afraid completely passed me by. It is specially hard to understand when people just are not motivated to do anything when you have vision and others around you just don’t.
I only found my purpose at age 55. Until that time I was just scrabbling around in the dark trying my best to do everything right. But really there was not much to get up to in the morning. Now, I am unstoppable on my mission because I have got all of life’s admin (marriage, children, 9 to 5 job etc,) out of the way and I know where I am going, why I am going there, and how to get there. Its awesome. I think waiting all those years gave me skills I needed which I would not have had otherwise. So in my case the timing was perfect.
By the time you get to 55 maybe the real higher purpose of your life will be revealed and with all your experience I can only see this as a magnificent journey awaiting you. In the meantime lock in the value of each breath you have, as you are doing now, so that when your time comes to leave the planet you go without any regrets.