I think you probably have a good shot at success. In fact, in my experience with emancipation motions (25 years so far), where a kid is failing in college, there's usually other evidence of his unproductive lifestyle. As you may know, the judge will be considering whether the child is now "outside the sphere of influence of his parents." In other words, is he acting independently, doing his own things, making his own life decisions (if even bad ones)? Or is a homebody, who still lives with your ex, and who relies on her support? If you can show that he's emancipated both in terms of his "independent" behavior AND in terms of his failure to pursuit of college, your chances will be stronger.
Feel free to call me if you'd like help with this. We have offices in Roseland, Newark and Short Hills.
Mark S. Guralnick, Esq.
Certified Family Law Attorney