Oooh I'm sorry, I forgot to add in the actual link in my previous post:
http://ark.intel.com/compare/77480,77775
Pentium graphics are 'Intel HD Graphics' where the i3 has got an Intel HD 4400 chip.
The graphics part of the Celeron and Pentium series are often not specifically mentioned so I'm assuming they're not worth writing about
An APU will be unnecessary. It will draw more power and produce more noise as the budget doesn't allow for an aftermarket cooling solution. Your client won't need the extra GPU power either.
Have you heard back from him yet?