Drop him a note - Idioms by The Free Dictionary
drop (one) a note (redirected from drop him a note)
drop (one) a note
To send one a letter or message. I always try to drop Janet a note around her birthday so that she knows I'm thinking of her.
drop somebody a ˈline/ˈnote (informal) write a short letter, message, etc. to somebody: I dropped her a line inviting her to my birthday party.