There were devices alike smartphones in 2005. Pretty popular in Germany too. Maybe he had one of these, or just has a dumb phone (most had note taking abilities and calendars and notifications) but the editor changed it? Sony Ericsson had some very powerful phones, and Nokia too, both very popular back then. You could even run apps (J2ME), I had one for public transit schedules and one for school grades and timetables.

This one was wildly popular in Europe, earlier models had similar functionalities: https://en.m.wikipedia.org/wiki/Sony_Ericsson_K750