From what I gather from the article linked above, he privately gave his expert opinion as a linguist regarding a passage of legal text. To make the claim that he "absolutely assisted", you'd have to presume it wasn't something he'd do for anyone else, that he expected it to be used (apparently he claimed otherwise?), and that it actually helped, despite seeming completely off-the-wall. Did I miss anything?

And even so, any one of us can hire an expert witness to make a statement like that. Especially big-shot professors. They aren't cheap I bet, but they surely don't cost 6 million bucks per line.