he wouldnt have been allowed in the elections if he didnt have actual members on the list, they actually check that stuff. I dont know about the inner working of the PVV, but there are actual members. Wether they are allowed to think for themselves is a different question altogether.
Just by the way, this list has the number of parties that applied for the elections and the number that is actually participating: https://www.kiesraad.nl/binaries/kiesraad/documenten/publicaties/2012/07/31/historisch-overzicht-registratie-en-deelname-partijen-aan-tweede-kamerverkiezing-1994-2017/historisch+overzicht+registratie+en+deelname+partijen+aan+Tweede+Kamer+1994-2017.pdf
Yellow bar is applied, blue is participating, year is at the bottom.
Edit: Its a pdf just fyi.