I think college
can definitely expand one's horizons, help you understand how much you
don't know and, maybe gain a bit of humility and flexibility in the process.
However, this product of a college education is by no means guaranteed and some people are just going to be stubborn in the face of a challenge, whatever they encounter. I can't tell you which kind of guy your step-brother-in-law is, but I'm glad it appears you have a good humor about the whole thing.