You find yourself in the unfortunate position of your son or daughter being dismissed from their college or university. It's not simply a matter of just not paying tuition. If it's owed to the school, the school unfortunately will seek to get that money either directly from the parents or potentially sending them out to collections if it's not obtained from the parents. You can't just, in most instances, not pay.
The question that would have to be asked is, is the school within its rights to be dismissing the student? Is the school acting appropriately in other words, or are there some due process considerations or other concerns that have led to this point? You have to try to obviously do what can be done to stop the dismissal, whether that's appealing the decision or taking other steps to the school if otherwise appropriate, say by engaging with the school's attorney or other administrators as may be appropriate to the circumstances.
In terms of tuition, generally that is owed even if a student is suspended or expelled if it takes place during the course of the semester. Having an experienced attorney advisor will be your best ally to help you understand and navigate the process and they should be involved as early as possible in a case to try to prevent such an occurrence.