Membership is free.
If he turns up early enough on the day, then alternates is an option.
There appears to be still the odd thread going up for seat exchange.
There"s roughly been 2-4 alternates at the previous events, normally with a list of 3x 4x that many players wanting to get in.
Why not get him on the forum and try and get a seat in advance, that would save any hassle on the day.