From personal experience I entered the engineering department of an OEM with an engineering degree, as did others at the same time. There were some 'pure science' graduates as well, and some who worked up from the draughtsman or shop floor route, but none from hands-on maintenance. Knowledge of aeroplanes was desirable but not essential, and could be learned, as the work consisted of designing and analysing the performance of components and sub-systems off the aircraft. The OEM I worked for also provided a good amount of job related training, none of which was Part-66 (or BCAR at the time).
What I'm saying is design and maintenance are two quite different sets of disciplines and the training for one does not necessarily coincide with the other. As I found myself when making the transition from industry to maintenance!
I'm not knocking your advice 400 and apologies if I was a bit harsh up there - the willingness to help entrants to the industry is not to be sniffed at either. I'm really just saying the job and knowledge requirements between design and maintenance are quite different (at least at the entry level - they tend to overlap further up the career ladder). In all honesty then, he has a degree which is the main qualification for most design/development jobs, he doesn't need Part-66, just the tenacity to research suitable employers and get selling himself. No guarantees he'll succeed, yes it's a competitive market, but you gotta start somewhere.