My brother proposed this, would it actually work? Obviously are going to start rolling lots of red dice against yourself, but is it actually legal?

This:

Do normal maneuver, collide, trigger Dauntless(use daredevil(trigger dauntless(use daredevil, gain a stress), gain a stress), gain a stress), gain a stress. You can nest them as many times as you want, as long as you roll damage on yourself each daredevil use

You can only take an action once per turn. So it wokld work the first time for double stress

You can do the Oicunn Double-Tap with the aforementioned pilot, dauntless title, daredevil (likely with engine upgrade) and Yorr in the shuttle.

Step one, make sure Yorr will be within range after you move the decimator.

Step 2 hit an enemy with the decimator "Dauntless" get an action after you hit choose daredevil, Yorr will eat the stress from the Dauntless' action and from daredevil. Daredevil will likely hit again, you can now do another action now, as daredevil is considered a maneuver, but the stress this time will stay on the Dauntless.

You have now hit twice with the Oicunn Double-Tap. It works, but is not reliable repeatedly.

Also, actions can only be done once per turn, so even if you could find a way to eat/ignore the stress, daredevil can only be used once