You need to login on his account, as you will only be shown registrations applicable to you on your account.
Bit of a pain, although he doesn't have a problem giving me his password, but I've already had another ask me to do the same, as he's at the Olympics (not tech illiterate!)
I usually do all the organising, as my job has always allowed me to, but I thought having them on my f+f would save me storing passwords. Hopefully, if they are successful in ballot, I can use my account and purchase for them like before.