misc_mg42 has no events listed, but in any case you could only then work with any mg42s with an existing scriptname definition (BTW Hobbits BSP reader does not handle misc_mg42 entities). Really you would need to use some other event in the game or add a func_timer to trigger the self repair periodically. To see how to use a func timer you can check the weather events I added to a couple of maps (UJE_hospital_sniper, md_bridge) or the mortars exploding (shooter_mortar) I added to Ammodepot.
You can also look at ae_sniper_night where I scripted in 2 misc_mg42s (since you may not be able to find targetnames for the existing ones).
I won't be able to spend much time looking at your waypoints before Sunday. Sorry.