joining a guild on a different server
The only meaningful use server has is WvW. If you arent interested in that it will not affect you at all. Servers basically dont exsist out side of wvw.
[Sane]-Order of the Insane Disorder
Melanessa-Necromancer Cymaniel-Scrapper
Minikata-Guardian Shadyne-Elementalist -FA-
Melanessa-Necromancer Cymaniel-Scrapper
Minikata-Guardian Shadyne-Elementalist -FA-
They merged PvE servers together long ago. As long as your son is in the same data group as you (NA or EU) he’ll have no troubles with guild access or grouping up in PvE.