@carolinseattle,
"when I was later making massive deletes of his email I someone found lots of really old trashed email from last November popping up on his account. Never happned on my accounts. I am wondering if it is using the trash all feature."
This does indeed sound similar to the behaviour I described, except that the emails "resurrected" by using the Trash All / Delete All feature, are only emails that have been previously handled by the device. Therefore, if you are seeing emails "resurrected" that haven't previously been handled by the device, I suggest you have another issue. Sorry, it wasn't clear to me from your post.
1) Are your email accounts also POP? If so it's strange that you haven't seen the same behaviour on your accounts.
2) Does "Trash / Trash All" always read that or is it like mine and sometimes read... "Delete / Delete All"?!
Good luck with your Apple Support call.