In one sense, all the major automakers sourced parts from outside manufacturers. Sometimes identical components, wound up on different makes. That said, sounds like he is generally full of it, and not just himself.

In future dealings, you could always find written proof, from several sources, that contradict what he has to say and confront him. Of course, he will continue to just dodge and weave and make excuses, but he'll eventually realize you're not so easily fooled.

You don't need to be Nasty about it, just factual. If you do it in front of other people, be prepared for a battle, as his ego will be on the line.

Now that you know he's really a false-expert, keep what he says with that in mind. If you suspect he's wrong, look it up or ask here.

If he's really that full-of-himself, others have or will recognize it. In the future, you could be cordial, but generally avoid him.

Over time, if you stick with it, read and look into the subject, you'll gain your own expertise. It simply takes time, but you're on the right track.