Draw:


It is customary to make your move before offering a draw. Maybe your opponent will accept after you play your next move.

Yes: you will lose if you don't make your move, unless your opponent accepts the draw before your time runs out; when you offer a draw on your move, your opponent has until he makes his next move to respond; after that, it's an automatic decline. As said, he has the right to wait until you make your move before accepting or declining.
It's quite likely actually that he just hasn't checked on this game since his last move there -- that's very common.