most likely it's what moloch said, but don't go and think it's because of indiffernces, it could be quintin has to move away so he can't see Sean and you anymore.
It could also mean that Quintin is feeling lonely for some reason and you pick that up by visions? What kind of connection do you have with him, perhaps you see what he feels?
Don't jump to any conclusions before you get more date to process on!!!! it could be millions of reasons why you only see him now.
It's best not to worry about something when you have but seen a fraction of the whole.
"Passion rules reason, for better or for worse" Keep to your senses and everything will work itself out.