The next time you have a friend working on a project at your mutual place of work, do not get involved. Just don’t.
Do not send said friend pictures of the project’s progress so that s/he will become intimidated and not complete his/her portion.
Do not constantly try to explain said friend’s lack of progress/updates to your fellow coworkers.
Do not nag your friend to finish his/her part of the project.
Do not get involved. Do not open your mouth. Do nothing. Seriously, just don’t.