Just tell you a story. With my help, one of my former classmate got a job a few month ago. He sent me an email, saying" Next time you come, I will treat you well". I responded: " Did you not treat me well before?"
I underdtand you want to say "thank you". I won't be scared even if you say
"thanks a billion!". But you could not say anything in other's name, because you are not authorized.
Hald kidding, half advising.