Typically, non-citizens admitted on crewmen visas are not eligible for adjustment of status. In a published case, the Eleventh Circuit determined that the beneficiary of such visa, who is subsequently granted medical parole, is still ineligible for adjustment of status. The subsequent parole does not trump the status a crewman.
The full text of Reganit v. Sec. of DHS can be found here: http://media.ca11.uscourts.gov/opinions/pub/files/201510784.pdf