How to deal with a team colleague submiting a bad article?
As a teacher, if I were to put a student in a team, is for the student to join and learn; and possibly (as it may be your case), to relieve the team from some tedious work. And actually, writing down a paper could be a good way of making sure he understands everything that has been done. Assuming there is no favouritism, I don't have any reason to make the guy get "research points" if he doesn't learn something in the process. So, if I am convinced he is affecting negatively an otherwise successful team, he is going to get little sympathy from me.

On the other hand, you are in a bit of a "he said-she said" situation, so you have to be careful and show that you have tried to collaborate with your teammate and attempted to solve the problem in a civilised manner. Show that when he joined the team, you didn't just dump the task on his lap and forget about him, but you actively tried to help and teach him what you did (because you tried to help, right?).