I'd definitely call now if you haven't heard anything back. Just let him know you were starting to worry a bit. Given how frequently you guys talk, it shouldn't seem clingy. Hopefully, everything is alright with him.
“This planet has - or rather had - a problem, which was this: most of the people living on it were unhappy for pretty much of the time. Many solutions were suggested for this problem, but most of these were largely concerned with the movement of small green pieces of paper, which was odd because on the whole it wasn't the small green pieces of paper that were unhappy.” ― Douglas Adams, The Hitchhiker's Guide to the Galaxy