I joke that people in TWHL insists you need to edit the half-life SDK code and produce your own custom DLLs at the slightest problem but I'm afraid this is the case for this one.
Yup, that's the case.
More specifically, the battery percentage is
there, the first highlighted line of code move the starting point a slightly bit to the right of the H.E.V. suit icons (empty and full). The second one actually print the percentage.
As for the line you're refering to, it's called a "divider" and it's part of the health HUD. The code you need to remove is
there (the highlighted one).