I suspect that most CFD programs were, at least originally, written by engineers. Many were distributed as source code (and almost always written in Fortran, because the Fortran community has always placed a great deal of importance on code portability).
Solving PDE's is non-trivial...
Britain has many fine universities with aeronautical programs. Engineering also requires much more writing than many people believe; depending on the subspeciality, your son could easily spend 75% of his work time writing various documents.
Fluency in written English is crucial. Fluency in...