Please check both sentences and let me know what is difference between them.
He is an inspiration for us.
He is an inspiration to us.
We wouldn't really say that someone is a inspiration for us. A person can "inspire us" or be "an inspiration to us." A person can also be the inspiration for a song, a book, a movie, etc.
In other words...
"inspiration to/or for somebody" =a person or thing that makes you want to be better, more sucessful,etc. So both mean the same thing. Also, we can say:"an inspiration for something" example:"We're searching for some inspiration for a new car design."