It’s very common behavior, managers are often not willing to confront an employee who is clearly not pulling his/her weight. It’s very tricky, get it wrong and you end up with an unfair dismissal case, unless an employee has a clear achievement or performance target, dismissal can be hazardous.
As you seem to be a team manager or leader in a larger organization you should report to your superiors and let them deal with it. Often the easiest way is to have a reorganization, reduce staffing levels and pay any redundancy due to those leaving.
Being a manager is hard you need to motivate your colleagues to be productive but you are paid by the boss to do that effectively and sometime hard decisions have to be made, getting involved in personal problems makes that more difficult.