Sorry to hear about Eurac's departure. I've seen many friends leave. Sometimes they come back and sometimes they leave for good. But remember that this is just a game and RL comes first. If he didn't share with you the reasons behind his leaving PS then perhaps it's something he wanted to keep private. It's good to let him know he'll be missed and I'm sure he'll appreciate it. Maybe he just needs a little time and it's better if players keep in mind that even though we can make friends through Planeshift, most of those relationships are just game acquaintances and do not really have that much meaning IRL. And for those that do, PS is only one way to reach them so you can still stay in touch.
And as far as the House of Games goes, things like this put guilds to the test. A strong guild should survive its creators. Eurac was the leader but he was also only one of its members. It's up to the rest to prove if the guild has the strength to stand on its own now, and it should. I don't see a reason why this guild should not continue to exist.