The person coming back should not have to explain every private reason they were gone.

Absence invites curiosity, and curiosity dresses itself up as concern. But an illness, a loss, a family situation or a stretch of not coping are not owed to a room simply because the room noticed a gap. Requiring the account before the welcome makes returning cost more than staying away.

When somebody reappears, greet them as though nothing needs explaining. Ask about today rather than the missing months, and let them tell you the rest whenever, or if, they want to.