Friend and I have no "Join In" option
Are you both in the same region (EU or US)? If one of you is EU and the other is US, you won’t be able to play together.
That’s what it was! Hadn’t bother checking because we’d been able to play together a couple years ago (we were on the same server). But in the time we’ve been away, his account was hacked and they moved him to an EU server. Thanks!
You’re welcome.
If, as stated, your friend has only low-level characters, he might consider deleting all his characters and transferring (at no cost) to your server. He can place any non-soul-bound items in the bank, and they will transfer with his account.
http://wiki.guildwars2.com/wiki/World#Transferring
Good luck.