When you have a child, you have general expectations of who, in your daily lives, are considered important people. Like friends, family, teachers, team coaches, etc. When you have a child with special needs, the additional important people in your lives aren't who you may have expected.
Yes, this is the card I wrote this year.

Dear Fed Ex Driver,
We see you once a month. You drive up with our package, our dogs give you grief, and you wait patiently while I shoo them into their crate. I sign and accept the package, thanking you and wishing you a good day. What you may not realize is that you are a very important person in our lives and we very much appreciate what you do.
The package you deliver every month, is medication that keeps our son alive and healthy. It's ok if you didn't know this. And it's ok if our future monthly encounters remain the same routine. But in the spirit of the holiday season, we wanted to give you a little something as a token of our appreciation.
So, for one, we really hope you like chocolate. :-) And secondly, have a very happy holiday!
See you next month,
The ----- Family