(personal opinion), but to me a process that encourages these kind of drills is pretty broken, these drills are ( most of the time) not related to the real world problems the company faces on a day to day basis, imo, a better process ( but not perfect) would be to test candidates on problems related to the ones you face at the company combined with cultural fit / pair programming sessions, even tho not perfect it can attract more candidates that are more fitting to the company and the team.
this doesn't mean the tests and problems need to be easy or an easy pass, they can be just as hard or even harder to solve, depending on the problems you guys face, i often hear people defending the drills because "people just want a for loop problem and fizzbuzz and easy pass", which is not the case for many seniors engineers that would like a decent challenge related to what the company works on.
If I understand you correctly, the bad issue is tests by drilling for drilling sake. I agree with you but follow me on this:
Am I wrong to say that he as one person is in no position to change the process?
What I mean is that his choices are either to just go through the hoops and reject to the drills because they are not representative for his ability, or accept this testing but not stamp negative results on his quality as a person or developer.
In the end he is not defending the process too strongly; is seems to me that he simply wants a formula to navigate it.
this doesn't mean the tests and problems need to be easy or an easy pass, they can be just as hard or even harder to solve, depending on the problems you guys face, i often hear people defending the drills because "people just want a for loop problem and fizzbuzz and easy pass", which is not the case for many seniors engineers that would like a decent challenge related to what the company works on.