Oh he does know. He does know a lot, that much is quite obvious. The problem is his teaching experience, or how he communicates his knowledge. That leaves a lot to be admired especially when we compare him to the others that came from similar backgrounds. Those set high standards maybe. I think this is his fourth year of teaching (not sure). Its as you say its a passion. He does not vary his style or even the pitch of his voice. Makes really hard to focus for an hour.
May be age as well; here he wont last. I always teach students to put their questions and read ahead before next class. this way they wont fall apart and be ready to engage with good questions... also of key ... no questions are irrelevant, you need to make a student feel he/she has something to contribute and just as they learn, i also learn.
I was so fortunate, i had some of the best profs who were world authorities in their field. They encouraged us to go away from textbooks and explore on our own; yes it got us into such trouble for a particular work but we were able to justify it and we moved on.
Dont stop after your 4th year; get your MSc and go into the industry where you are working. Practise your skill and get more practical knowledge then go back and if you have an idea, make it your thesis and there will always be bumps, face them.
Dont stop learning is my guidance to you. Learning is a lifetime career. I see people stagnate once they stop learning. Another aspect - get to know,live and breath project management - Agile/scrum/different methodologies use them.
Between 12 major major projects in my life time, with already 1 PhD, i embarked on another PhD - busy with it.
++ Moderators - sorry i went off topic but as an researcher who loves teaching, if I can use this as an encouragement medium to uplift students.