Sorry, it isn’t a typeface. Hand lettering by Fieker Brothers.
Good find, Kevin. James, the best way to mimic this is by hiring a lettering artist. if you must have a font, check out Flood, Handelson Two, and Manus.
It is most definitely copyrighted. I suggest using one of the typefaces suggested by Stewf instead, and explain to your client that you can’t—and won’t—break the law to create their shirt.
A few more suggestions: