Whether she's still doing her work would be pretty easy for you to determine.
I work from home pretty much every day of the week. My manager is in another state, and clients and contacts are all over the globe. There is zero practical reason for me to ever go into the office, and multiple reasons why, at least for me, staying home is incredibly superior.
I'm rather surprised that any IT division that isn't either directly customer facing or has a hands / feet hardware maintenance factor even bothers having offices.