A safe assumption more or less if he is arriving on a Metra (commuter rail) train. Not safe if Amtrak.

The Jackson CTA stop says it is handicapped accessible on the map. Since the blue line is a subway at Jackson, I would assume this means an elevator though I could be wrong. Clark/Lake, in the Thompson Center, is pretty certain to have an elevator. But don't hold me to any of this, since I don't pay attention to what stops have elevators or not.