I think just reading his Wikipedia entry, I caught someone at CNN being kind:

O’Brien left CNN in December 2008. He was rehired by CNN as an aviation analyst in March, 2014.

2008–present: owner Miles O’Brien Productions, LLC in Washington, DC

In February, 2014, O'Brien was injured when a Pelican case filled with television equipment fell on his left forearm, causing acute compartment syndrome and resulting in the amputation of his left arm above the elbow.

So, the month after a gruesome injury he was re-hired by CNN, who probably have a pretty good medical plan, better than what he probably would have had when he was self-employed. Maybe not, maybe it's just coincidence. But, it's nicer to believe that someone at CNN thought they should look out for a former colleague / friend who needed some help.