Doesnt that say the 1099K was issued by INTU, that sounds like Intuit to me (Oh I just saw in one of the posts about, you had this information, lots of dig through up there, sorry). 

What kind of business is he in?  Does he use Intuit for any type of payment processing?

Have you pulled a wage and income transcript?  Is it on there? 

I have a client with Misidentified Income on multiple 1099NECs  attributed to her on a CP2000 (she's never been self employed or in the healthcare field where these 1099NECs originated from), but when I pull a wage and income transcript it shows nothing, Ive been fighting with IRS for a year now to get this fixed.