Underperforming Team Member

Had a discussion on underperforming team member issue.
It started with a topic that whether underperforming unprofessional team member be allowed to attend a meeting if he/she turns in late for the meeting. To add to the confusion that team member is your friend.
My way of managing such project-
Underperforming unprofessional team member: Lets keep friendship issue aside. The fact that he/she is ur team member indicates that he/she has a potential to contribute. As a manager u should be able to tap in his/her potential. If I disallow him/her from attending the meeting, I will miss on his/her inputs on the task of the project. Based on 80-20 principle, if he/she is going to contribute something in 20% of the input that will give result to 80% output, my loss will be huge if I miss on his/her inputs. He/She may have valid reasons for coming late. But in any case I can not miss on the inputs.

Friend: If that person is ur friend, u should know what r the reasons behind such a behaviour. U should help that person deal with those issues and should have courage to forgive that person and make up for that person on professional front. Of course there is difference between friendship of convenience/pleasure and real friendship(Friend I am talking about is real friend).