Another thing is: it's really difficult to point to specific cases that really are "HR-worthy". That's the nature of passive-aggressive behavior. His treatment of another engineer, who has since been fired for performance, early this year really did qualify for HR based on how distressed the other employee was.
I think I may have to bring this up to my manager's manager, since my manager doesn't want to. It'll hurt my relationship with my manager, but I think this is feedback he really does need to hear and receive, or he'll just keep tolerating competent jerks on his teams.
Several other employees have had issues with him. The sense I get is they're really just seeking peace at this point and it's clear they're avoiding him. Since he's been there since the beginning he knows a lot that no one else does, but they rarely approach him for help -- he's made it clear to me in early 1:1s he isn't interested in investing more time in trying to up-level his peers.
He does have a good relationship with a junior engineer on the team, though, and may be developing a good one with another engineer that he probably has more respect for than me.