He was originally pulled in when Cohen hired his law firm, DuBoff, Dorband, Cushing and King, to litigate against people using Cohen's Sex.com "trademark". It is a measure of Dorband's persuasive abilities that several rich, powerful and unremitting players in the adult industry caved in to the pressure, especially when you consider that Cohen's trademark wasn't worth the paper it wasn't written on.
Dorband was forced to tread a very fine line, having to defend Cohen's actions and make statements in court that were just the right side of outright lies. Dorband's main job was to destroy or otherwise hold up Kremen case against Cohen, and he did so extremely effectively. It was thanks to Dorband's force that Kremen's lawyers redrafted their complaint no less than four times before finally entering court. The delays in getting it to court came within a whisker of bankrupting Kremen, at which point the whole case would have fallen.
But when vital court documents disappeared from a copying store and Kremen provided the video evidence that Cohen in person had stolen them, it was effectively the end of the case and Dorband relationship with Cohen. He continued to represent Cohen for a short while but eventually left the case, and then his own law firm.
It's uncertain whether the fact that Cohen still owes the law firm a large sum of money led to Dorband leaving the case or not. It certainly wasn't on good terms - with Cohen laying blame on Dorband at a deposition Cohen was forced to give in jail in late 2005.
Dorband now works as in-house lawyer for an insurance company in Portland, Oregon.