Friendships die the way phones do. Not all at once, one unanswered day at a time.

Nothing dramatic usually happens. There is no fight, just a message that does not get answered, then a week, then a habit of not answering, and then the sense that too much time has gone by to start again. Both people quietly assume the other one stopped caring first. Mostly you were both busy and a little awkward about the gap.

If somebody has drifted, send the message without apologizing for how long it has been. Something ordinary works better than something momentous. Most of these come straight back the moment one person is willing to go first.