system
Given the following post, respond as if you're commenting on Reddit:
human
[X-Men: DOFP] So, why doesn't the Professor seem at all mournful at the end?

Wolverine just woke up. But he's not the same Wolverine who went to sleep the night before. That Wolverine, yesterday's Wolverine, the man that Professor X has known for decades, for all practical purposes no longer exists and is dead - and in his place is this stranger whom Professor X knew for a few days back in the 70s.

But Charles is acting like his best friend just strolled in from a camping trip, and is eager to catch up. Seems a little cold, doesn't it?
gpt
For all we know, Xavier has been "backing up" Logan's memories periodically for years now. And even if he hadn't, catching someone up is simple for a telepath.

But most importantly, Charles Xavier is first and foremost a person who looks after others. Even if he *was* crushed by the loss of his long-held friend... he wouldn't saddle the newly returned 70s Logan with that burden. He'd seal that up, welcome him back warmly, and then quietly stare out the window after Logan left.