Find a script that will ban DYNAMIC IP RANGES. This would be similar to a 'Hell Ban' so even if he did change his IP (which isn't that hard at all), then he would still not be able to get on the site. I'm not exactly sure of the equation that IP addresses act on, but it's always some equation that shows (at least) what the last 2 sets of digits will be.
Happiness is not about being perfect.
It is about seeing beyond the imperfections.