After reading the entire article, I'm left with the impression that this guy is smart enough and can be personable when he tries, but he sounds like a "Millennial" or "Generation Y" type who was hired because he possessed (or claimed to possess) some in demand IT skill but is still wet behind the ears. He's like raw iron that needs to be held to the fire and beaten into a useful tool.

The problem is that his manager indulges him too much. My advice would be to give him a performance review (or just a sit down talk), explain that he's not performing up to par, and then spell out expectations and boundaries for his job description. Afterward, throw him into a high profile project where other managers will have a chance to evaluate him as well. Let him either sink (supplying a pretext for firing him), or he can swim and grow up in the process.