As team lead are you the persons manager? If so you should have every right to go to hr to either terminate or start a performance improvement plan. If your a

As team lead are you the persons manager? If so you should have every right to go to hr to either terminate or start a performance improvement plan. If your a team lead with no hire/fire power you need to go to your department head (and rally those whoa agree with you to do the same) and be blunt. "X is is not performing to expectations on top of that the way X is not performing is disrupting, impeding, and alienating other members of the team and its now become not just a performance issue but one of employee attrition". This makes it about X vs the rest of the team/department and allows him to clearly see what is actually at risk. Its very unlikely 1 person is so valued that a manager would accept major turnover in their department.