Yes, the 4 year old counts. Everyone over the age of 2 must be listed on the Access List to enter the Drill Hall for PIR. Anyone not on the Access List should remain at the hotel and watch the Live Stream at http://www.livestream.com/usnavyrtc or http://navylive.dodlive.mil/. There are no tickets, it's names on the Access List. Who did he list on The Form Letter? Those are the people that he plans to list when the time comes to submit the names 3 to 10 days before PIR and only those guests will be admitted to the Drill Hall. Those not on the Access List may be turned away or they may be permitted to watch the Live Stream in the Chapel (don't plan on that as that is not guaranteed and should only be used when staying at the hotel is not an option).
NO, he cannot have a buddy put down names for him; it was allowed in the past, but is no longer authorized. The RTC considers that a breach of security and bad things could happen. Consequences that have been mentioned are any or all of the following: all guests listed by both could be denied access to the Drill Hall for PIR or just the one/s found to not belong to the Sailor could be denied access; he and his buddy could lose Liberty; he and his buddy could be delayed in leaving for "A" School or training. Those are not things that your SR wants.
Check your My Page.