What are some good things to say via email?

Well,I for one have no relationship with your colleague,have no idea about this persons family member,and no idea what's even going on in this colleagues life.
So,given all that....how would I even be able to tell you what to send in an email to this colleague.I have no idea who this person even is,or anything about this persons life....personal/professional life.

Surly you can figure this simply task out for yourself.You honestly need others advice on what to tell one of your colleagues in a simple email.This is a personal situation your faced with,and no one here knows what's actually going on with this colleague of yours.Do you need other people to tell you what you should eat for breakfast,lunch and dinner too.
Good luck either way.

Email your honest feelings.Only you know this colleague.Not anyone here!