Can a team leader tell his worker that nobody wants to work with her?

This team leader A listened to fellow workers that they do not want to work with B. Then this Team leader goes to tell B so n so don’t want to work her. He can also point at someone who happens to be around by telling B the same story. This includes in group chat as well. This team leader doesn’t seem to be in his right mind and how could he do this kind of thing to B. He should solve the situation instead of trying to create more psychological trauma to B. I believe B doesn’t cause any problem at work. Please advise n I know B who is not a trouble maker. Please kindly advise and B needs help desperately. Thanks