Relatives of my husband were on that flight. They were interviewed and saw first-hand that the man had no passport.
http://tinyurl.com/y8l2w46
I checked the requirements for borading an aircraft at Schiphol Airport. There are alternatives to passports if you’re from a Schengen country, which is most of mainland Europe. The UK is not one of them and Nigeria and Sudan certainly aren’t. Otherwise one has to have a valid passport at check-in.
I don’t doubt your relatives saw what they saw but from what I’ve read the guy must have had to produce a passport at some point. If not, a bunch of people need to go to jail.