This is a pretty common scenario, and the first thing to do is go through the ENTIRE car and look for the lug nut key. I’ll give 70-30 odds that it is buried somewhere deep in the spare tire well, glove box, or someplace that your kid forgot to look – and if it isn’t, this process still provides a great excuse to get junior to clean up his new sled and become more familiar with his car.
Next steps: try to determine what brand of lug nut lock is being used, and then go online or to a local tire store and see if you can order a replacement. McGard, one of the biggest names in the industry has a helpful online guide.
Failing that, you’re looking at a variety of brute-force removal methods that might involve cutting off the offending lug nut, or hammering a socket over the entire assembly and getting it off that way. Go to YouTube for examples, but be sure to use common sense and best safety practices, to avoid damaging your wheels or wheel studs. If you’re unsure, take it to a professional. ~ Bill