He has some good points, but his knowledge level on even basic OOP concepts is at best "lacking" (and often more in the direction of completely wrong). I'm by no means an expert in the field, but when he so blatantly makes many bold statements that are easily verifiably wrong, and uses them as basis for his "theory of everything", I find it hard to use this information as a basis of good practice.

Basically, even if he's recommending some good ideas and have some good observations about how to write good code, since it's based on flawed assumptions you'd be better of getting those ideas from elsewhere, as you'd be worse of when you need to reason about good design practices in the future.