Very useful info. Seems like the openGL-api renpy uses messes up somehow. Not uncommon, just rare. First make sure to update your graphics-driver (know it's gliché, but in your case it's very relevant!).
If upgrading your video drivers does not fix the problem, you should disable OpenGL support. To disable OpenGL support:
1. Hold down shift while starting Ren'Py.
2. From the "Graphics Acceleration" menu that appears, choose "Prefer Software Renderer".
3. Choose "Continue".
Found a few different way of initiating videos. Dont know the if they're different, but try these codes ingame along with those before
Code:
play movie "image/extras/day 13/ani_day13motel_dad_jerkoff.webm"
renpy.movie_cutscene("images/extras/day 13/ani_day13motel_dad_jerkoff.webm",loops=-1)
Do any of these start the video ingame?