I agree, and I think that inability to explain things is his greatest weakness.

At this point I'm not convinced he's a quack, because there could be other reasons he can't explain his theories:

1. He's not as good a communicator as he thinks he is.

2. The theory isn't fully enough worked out to be distilled down for laypeople.

3. The mathematical tools of the theory are so obscure that most people have no intuitive way of relating to them.

If it's any of those three, those are challenges than can and should be overcome.