if you need to keep him, how about trying to not talk about the personal stuff and try and keep him focussed on work....why can he spend work time complaining to you? maybe cut the bad subjects off ,as in we need to work on this now....get off of the feeling subject and onto the work subject...hopefully he still want s to work...

....captain, do you really think you can change an employee? i struggle with this a lot....right now i have one who is treating my customers like an angel...and another who wont even get out of their way in an aisle....
i cant seem to change any behavior for very long....and how long should i try? ..some kinds could demoralize the whole place...
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.i kind of veer towards just getting rid of the bad apples...and if a new person cant find something to excell at i start cutting hours.....