No-one (sadly) has to have a recognised qualification, or be a member of a professional body to submit plans to the Local Authority.
He certainly shouldn't be advertising himself as an *Architect*, though, unless he has RIBA accreditation. He can, however, offer *Architectural Services*.
In your shoes I would certainly follow the advice of Nini74 and NOX. It may mean a little additional outlay on your part, but if that means you can claw any monies back.
Also, it may be worth having a word with your local bobbies. Depending upon all the circumstances this could also be viewed as 'theft' which takes it out of the Civil Court.