Some of the very first machines with Core2Duo processors are not "compatible" with Mountain Lion.
What? They are 64-bit machines! It is an arbitrary selection from Apple what is and is not supported. If he is on 10.6.X, Rosetta compatibility is already heavily diminished. In 10.7... even more so.
I've looked into this *A LOT* more than you realize AS. I stand by my words and recommendations.
And, YES it is that simple.
And Yes, you are scared for the wrong reasons about your "server".
Now granted if your server was 1500 miles away (like all of my work ones), that would be different. Or even 2 hours driving time away (like my personal one) that would also be scary... You have console access. That is not a big problem.
You really need to buck up, soon.