Yes, you did. But you didn't do it alone. Jenova killed him, more than you did.

['And if I had been strong enough, you wouldn't have'. This part is not said, but it's clear that once again, Vincent feels like he's failed to protect Sephiroth from himself.]

You'd better be there when he wakes up. You deserve everything he's got to tell you.

... I'll deal with the others.