That was my worry: the guy who writes 400 line functions/methods/subs is always gonna do just that when nobody is looking. I am assuming 2 to 4 years training

That was my worry: the guy who writes 400 line functions/methods/subs is always gonna do just that when nobody is looking. I am assuming 2 to 4 years training or education prior to this. If you haven't learned to subdivide long / deeply nested routines into smaller functions with defined inputs and outputs after 2 years, you probably just don't get it, and may never. That seems harsh, I suppose. But I've been doing this for a living for most of the last 30 years. When I started, I was 2 years into my CS degree. I've met too many code monkeys who might know some new API, but just congenitally cannot organize code to save their lives and write stuff I would not even have written as a 20 year old part timer going to school. Spend a few weeks to see if the guy can learn. If not, start documenting a "performance improvement plan" (there's a euphemism) so you can get rid of him.