are you trying to establish if they are working - i.e at their of work doing their job or whether they are still doing a job i.e is mrs x still employed at xxx doing xxx
or if they are alive or not, in which case a good prod should establish that.
short of asking them, you could try lookign them up on linkedIn & see if they have a profile on there - same with facebook, they might list their employment status
If you know the company they work for , they may have a staff list on their website
You could follow them or employ someone to do so...