Does he have any hobbies? Boy Scouts? Video Games? Play a musical instrument?
Perhaps you could ask her for some ideas?
He likes to video games but don't play that much. His mom said he does not really have any hobbies or nothing really stands out to her. I thought about making him something like a candy bar or spaghetti. Let me know what you think. (Most boys love to eat)
Candy bar cake sounds cute. 
Does he have a favorite beverage, i.e., Coke or bottle water, etc. - that would also make a cute (and somewhat personalized) cake.
Duplicate post, please also see:
http://forum.cakecentral.com/cake-decorating-ftopict-581942.html
my son loves Star Wars, I did a Yoda cake for him....find out if he's into certain movies
Why not focus on his Name? You can airbrush the cake several colors then use white icing to pipe "H B and his name" in bubble writing - filling the top of the cake.
OR I remember seeing in an older MBN where someone made the neatest cakes - all rounds - where they just piped *very, very neatly* their monogram in fancy script.
Quote by @%username% on %date%
%body%