Email lost during move

My husband was moving his Comcast email to his Gmail account folders.   Several hours later, he noted that all appeared to have moved (using the Apple Mail viewer). I then accidentally deleted his Gmail account on his device, instead of his Comcast account.  I re-added the gmail account.  However the items he moved from the Comcast mailbox are no longer seen in the Apple viewed.  

I felt all of the “moves” were at the server level, not the devise level.  Please advise- he’s not happy with me!!